Migrate to use RecyclerView-Selection library

Test: atest DocumentsUITests
Bug: 110482929
Change-Id: Icb99520ac48d120b8bed0ce461c5e4f2ff885c18

112 files changed, 798 insertions, 9662 deletions

diff --git a/build_apk.mk b/build_apk.mk
index c7955bc02..e8252f64f 100644
--- a/build_apk.mk
+++ b/build_apk.mk
@@ -10,7 +10,8 @@ LOCAL_STATIC_ANDROID_LIBRARIES := \
         androidx.legacy_legacy-support-v13 \
         androidx.design_design \
         androidx.transition_transition \
-        androidx.recyclerview_recyclerview
+        androidx.recyclerview_recyclerview \
+        androidx.recyclerview_recyclerview-selection
 
 LOCAL_USE_AAPT2 := true
 
diff --git a/src/com/android/documentsui/AbstractActionHandler.java b/src/com/android/documentsui/AbstractActionHandler.java
index 0bb327b0c..0eb308f8c 100644
--- a/src/com/android/documentsui/AbstractActionHandler.java
+++ b/src/com/android/documentsui/AbstractActionHandler.java
@@ -34,11 +34,15 @@ import android.net.Uri;
 import android.os.Bundle;
 import android.os.Parcelable;
 import android.provider.DocumentsContract;
-import androidx.annotation.VisibleForTesting;
 import android.util.Log;
 import android.util.Pair;
 import android.view.DragEvent;
 
+import androidx.annotation.VisibleForTesting;
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.SelectionTracker;
+
 import com.android.documentsui.AbstractActionHandler.CommonAddons;
 import com.android.documentsui.LoadDocStackTask.LoadDocStackCallback;
 import com.android.documentsui.base.BooleanConsumer;
@@ -57,10 +61,6 @@ import com.android.documentsui.queries.SearchViewManager;
 import com.android.documentsui.roots.GetRootDocumentTask;
 import com.android.documentsui.roots.LoadRootTask;
 import com.android.documentsui.roots.ProvidersAccess;
-import com.android.documentsui.selection.ContentLock;
-import com.android.documentsui.selection.MutableSelection;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 import com.android.documentsui.sidebar.EjectRootTask;
 import com.android.documentsui.ui.Snackbars;
 
@@ -93,7 +93,7 @@ public abstract class AbstractActionHandler<T extends Activity & CommonAddons>
     protected final ProvidersAccess mProviders;
     protected final DocumentsAccess mDocs;
     protected final FocusHandler mFocusHandler;
-    protected final SelectionHelper mSelectionMgr;
+    protected final SelectionTracker<String> mSelectionMgr;
     protected final SearchViewManager mSearchMgr;
     protected final Lookup<String, Executor> mExecutors;
     protected final Injector<?> mInjector;
@@ -227,7 +227,7 @@ public abstract class AbstractActionHandler<T extends Activity & CommonAddons>
     }
 
     @Override
-    public boolean openItem(ItemDetails doc, @ViewType int type, @ViewType int fallback) {
+    public boolean openItem(ItemDetails<String> doc, @ViewType int type, @ViewType int fallback) {
         throw new UnsupportedOperationException("Can't open document.");
     }
 
@@ -533,8 +533,8 @@ public abstract class AbstractActionHandler<T extends Activity & CommonAddons>
         loadRoot(Shared.getDefaultRootUri(mActivity));
     }
 
-    protected MutableSelection getStableSelection() {
-        MutableSelection selection = new MutableSelection();
+    protected MutableSelection<String> getStableSelection() {
+        MutableSelection<String> selection = new MutableSelection<>();
         mSelectionMgr.copySelection(selection);
         return selection;
     }
diff --git a/src/com/android/documentsui/ActionHandler.java b/src/com/android/documentsui/ActionHandler.java
index 53a746a4b..6f25f053b 100644
--- a/src/com/android/documentsui/ActionHandler.java
+++ b/src/com/android/documentsui/ActionHandler.java
@@ -24,12 +24,12 @@ import android.content.pm.ResolveInfo;
 import android.net.Uri;
 import android.view.DragEvent;
 
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+
 import com.android.documentsui.base.BooleanConsumer;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.DocumentStack;
 import com.android.documentsui.base.RootInfo;
-import com.android.documentsui.selection.ContentLock;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -37,6 +37,9 @@ import java.util.function.Consumer;
 
 import javax.annotation.Nullable;
 
+/**
+ * Interface to handle action for document.
+ */
 public interface ActionHandler {
 
     @IntDef({
@@ -110,7 +113,7 @@ public interface ActionHandler {
      * If container, then opens the container, otherwise views using the specified type of view.
      * If the primary view type is unavailable, then fallback to the alternative type of view.
      */
-    boolean openItem(ItemDetails doc, @ViewType int type, @ViewType int fallback);
+    boolean openItem(ItemDetails<String> doc, @ViewType int type, @ViewType int fallback);
 
     /**
      * This is called when user hovers over a doc for enough time during a drag n' drop, to open a
diff --git a/src/com/android/documentsui/ActionModeController.java b/src/com/android/documentsui/ActionModeController.java
index 4e0baef45..8b74dbf5a 100644
--- a/src/com/android/documentsui/ActionModeController.java
+++ b/src/com/android/documentsui/ActionModeController.java
@@ -31,33 +31,34 @@ import android.view.View;
 import com.android.documentsui.MenuManager.SelectionDetails;
 import com.android.documentsui.base.EventHandler;
 import com.android.documentsui.base.Menus;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.SelectionHelper.SelectionObserver;
 import com.android.documentsui.ui.MessageBuilder;
 
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.selection.SelectionTracker.SelectionObserver;
+
 /**
  * A controller that listens to selection changes and manages life cycles of action modes.
  */
-public class ActionModeController extends SelectionObserver
+public class ActionModeController extends SelectionObserver<String>
         implements ActionMode.Callback, ActionModeAddons {
 
     private static final String TAG = "ActionModeController";
 
     private final Activity mActivity;
-    private final SelectionHelper mSelectionMgr;
+    private final SelectionTracker<String> mSelectionMgr;
     private final MenuManager mMenuManager;
     private final MessageBuilder mMessages;
 
     private final ContentScope mScope = new ContentScope();
-    private final Selection mSelected = new Selection();
+    private final MutableSelection<String> mSelected = new MutableSelection<>();
 
     private @Nullable ActionMode mActionMode;
     private @Nullable Menu mMenu;
 
     public ActionModeController(
             Activity activity,
-            SelectionHelper selectionMgr,
+            SelectionTracker<String> selectionMgr,
             MenuManager menuManager,
             MessageBuilder messages) {
 
diff --git a/src/com/android/documentsui/BaseActivity.java b/src/com/android/documentsui/BaseActivity.java
index 8e4ea867e..7343fa888 100644
--- a/src/com/android/documentsui/BaseActivity.java
+++ b/src/com/android/documentsui/BaseActivity.java
@@ -16,8 +16,8 @@
 
 package com.android.documentsui;
 
-import static com.android.documentsui.base.SharedMinimal.DEBUG;
 import static com.android.documentsui.base.Shared.EXTRA_BENCHMARK;
+import static com.android.documentsui.base.SharedMinimal.DEBUG;
 import static com.android.documentsui.base.State.MODE_GRID;
 
 import android.app.Activity;
@@ -31,9 +31,6 @@ import android.os.Bundle;
 import android.os.MessageQueue.IdleHandler;
 import android.preference.PreferenceManager;
 import android.provider.DocumentsContract;
-import androidx.annotation.CallSuper;
-import androidx.annotation.LayoutRes;
-import androidx.annotation.VisibleForTesting;
 import android.util.Log;
 import android.view.KeyEvent;
 import android.view.Menu;
@@ -41,6 +38,10 @@ import android.view.MenuItem;
 import android.view.View;
 import android.widget.Toolbar;
 
+import androidx.annotation.CallSuper;
+import androidx.annotation.LayoutRes;
+import androidx.annotation.VisibleForTesting;
+
 import com.android.documentsui.AbstractActionHandler.CommonAddons;
 import com.android.documentsui.Injector.Injected;
 import com.android.documentsui.NavigationViewManager.Breadcrumb;
@@ -60,7 +61,6 @@ import com.android.documentsui.queries.CommandInterceptor;
 import com.android.documentsui.queries.SearchViewManager;
 import com.android.documentsui.queries.SearchViewManager.SearchManagerListener;
 import com.android.documentsui.roots.ProvidersCache;
-import com.android.documentsui.selection.Selection;
 import com.android.documentsui.sidebar.RootsFragment;
 import com.android.documentsui.sorting.SortController;
 import com.android.documentsui.sorting.SortModel;
@@ -82,7 +82,6 @@ public abstract class BaseActivity
     @Injected
     protected Injector<?> mInjector;
 
-    protected @Nullable RetainedState mRetainedState;
     protected ProvidersCache mProviders;
     protected DocumentsAccess mDocs;
     protected DrawerController mDrawer;
@@ -133,10 +132,6 @@ public abstract class BaseActivity
         mDrawer = DrawerController.create(this, mInjector.config);
         Metrics.logActivityLaunch(this, mState, intent);
 
-        // we're really interested in retainining state in our very complex
-        // DirectoryFragment. So we do a little code yoga to extend
-        // support to that fragment.
-        mRetainedState = (RetainedState) getLastNonConfigurationInstance();
         mProviders = DocumentsApplication.getProvidersCache(this);
         mDocs = DocumentsAccess.create(this);
 
@@ -524,29 +519,6 @@ public abstract class BaseActivity
     }
 
     @Override
-    protected void onRestoreInstanceState(Bundle state) {
-        super.onRestoreInstanceState(state);
-    }
-
-    /**
-     * Delegate ths call to the current fragment so it can save selection.
-     * Feel free to expand on this with other useful state.
-     */
-    @Override
-    public RetainedState onRetainNonConfigurationInstance() {
-        RetainedState retained = new RetainedState();
-        DirectoryFragment fragment = DirectoryFragment.get(getFragmentManager());
-        if (fragment != null) {
-            fragment.retainState(retained);
-        }
-        return retained;
-    }
-
-    public @Nullable RetainedState getRetainedState() {
-        return mRetainedState;
-    }
-
-    @Override
     public boolean isSearchExpanded() {
         return mSearchManager.isExpanded();
     }
@@ -662,14 +634,6 @@ public abstract class BaseActivity
         });
     }
 
-    public static final class RetainedState {
-        public @Nullable Selection selection;
-
-        public boolean hasSelection() {
-            return selection != null;
-        }
-    }
-
     @VisibleForTesting
     protected interface EventListener {
         /**
diff --git a/src/com/android/documentsui/ContentLock.java b/src/com/android/documentsui/ContentLock.java
new file mode 100644
index 000000000..d9f0346ca
--- /dev/null
+++ b/src/com/android/documentsui/ContentLock.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.documentsui;
+
+import android.annotation.Nullable;
+
+import androidx.annotation.GuardedBy;
+import androidx.recyclerview.selection.OperationMonitor;
+
+/**
+ * ContentLock provides a mechanism to block content from reloading while selection
+ * activities like gesture and band selection are active. Clients using live data
+ * (data loaded, for example by a {@link Loader}), should route calls to load
+ * content through this lock using {@link ContentLock#runWhenUnlocked(Runnable)}.
+ */
+public final class ContentLock {
+
+    private final OperationMonitor mMonitor = new OperationMonitor();
+
+    @GuardedBy("this")
+    private @Nullable Runnable mCallback;
+
+    public ContentLock() {
+        mMonitor.addListener(() -> {
+            if (!isLocked()) {
+                synchronized (this) {
+                    final Runnable callback = mCallback;
+                    if (callback != null) {
+                        callback.run();
+                        mCallback = null;
+                    }
+                }
+            }
+        });
+    }
+
+    public OperationMonitor getMonitor() {
+        return mMonitor;
+    }
+
+    /**
+     * Returns true if locked.
+     */
+    private boolean isLocked() {
+        return mMonitor.isStarted();
+    }
+
+    /**
+     * Attempts to run the given Runnable if not-locked, or else the Runnable is set to be ran next
+     * (replacing any previous set Runnables).
+     */
+    public synchronized void runWhenUnlocked(Runnable runnable) {
+        if (!isLocked()) {
+            runnable.run();
+        } else {
+            mCallback = runnable;
+        }
+    }
+}
diff --git a/src/com/android/documentsui/DirectoryLoader.java b/src/com/android/documentsui/DirectoryLoader.java
index eb3ab32c3..0a749fb65 100644
--- a/src/com/android/documentsui/DirectoryLoader.java
+++ b/src/com/android/documentsui/DirectoryLoader.java
@@ -43,7 +43,6 @@ import com.android.documentsui.base.FilteringCursorWrapper;
 import com.android.documentsui.base.Lookup;
 import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.roots.RootCursorWrapper;
-import com.android.documentsui.selection.ContentLock;
 import com.android.documentsui.sorting.SortModel;
 
 import android.os.FileUtils;
diff --git a/src/com/android/documentsui/DocsSelectionHelper.java b/src/com/android/documentsui/DocsSelectionHelper.java
index c788119a7..b7a720c8b 100644
--- a/src/com/android/documentsui/DocsSelectionHelper.java
+++ b/src/com/android/documentsui/DocsSelectionHelper.java
@@ -16,50 +16,42 @@
 
 package com.android.documentsui;
 
-import androidx.annotation.VisibleForTesting;
-import androidx.recyclerview.widget.RecyclerView;
+import android.os.Bundle;
+import android.view.MotionEvent;
 
-import com.android.documentsui.selection.DefaultSelectionHelper;
-import com.android.documentsui.selection.DefaultSelectionHelper.SelectionMode;
-import com.android.documentsui.selection.MutableSelection;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.SelectionHelper;
+import androidx.annotation.VisibleForTesting;
+import androidx.recyclerview.selection.ItemDetailsLookup;
+import androidx.recyclerview.selection.ItemKeyProvider;
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.Selection;
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.widget.RecyclerView.AdapterDataObserver;
 
 import java.util.Set;
 
-import javax.annotation.Nullable;
-
 /**
  * DocumentsUI SelectManager implementation that creates delegate instances
  * each time reset is called.
  */
-public final class DocsSelectionHelper extends SelectionHelper {
+public final class DocsSelectionHelper extends SelectionTracker<String> {
 
     private final DelegateFactory mFactory;
-    private final @SelectionMode int mSelectionMode;
 
     // initialize to a dummy object incase we get some input
     // event drive calls before we're properly initialized.
     // See: b/69306667.
-    private SelectionHelper mDelegate = new DummySelectionHelper();
+    private SelectionTracker<String> mDelegate = new DummySelectionTracker<>();
 
     @VisibleForTesting
-    DocsSelectionHelper(DelegateFactory factory, @SelectionMode int mode) {
+    DocsSelectionHelper(DelegateFactory factory) {
         mFactory = factory;
-        mSelectionMode = mode;
     }
 
-    public SelectionHelper reset(
-            RecyclerView.Adapter<?> adapter,
-            StableIdProvider stableIds,
-            SelectionPredicate canSetState) {
-
+    public void reset(SelectionTracker<String> selectionTracker) {
         if (mDelegate != null) {
             mDelegate.clearSelection();
         }
-
-        mDelegate = mFactory.create(mSelectionMode, adapter, stableIds, canSetState);
-        return this;
+        mDelegate = mFactory.create(selectionTracker);
     }
 
     @Override
@@ -73,12 +65,12 @@ public final class DocsSelectionHelper extends SelectionHelper {
     }
 
     @Override
-    public Selection getSelection() {
+    public Selection<String> getSelection() {
         return mDelegate.getSelection();
     }
 
     @Override
-    public void copySelection(Selection dest) {
+    public void copySelection(MutableSelection<String> dest) {
         mDelegate.copySelection(dest);
     }
 
@@ -94,18 +86,13 @@ public final class DocsSelectionHelper extends SelectionHelper {
     }
 
     @Override
-    public void restoreSelection(Selection other) {
-        mDelegate.restoreSelection(other);
-    }
-
-    @Override
     public boolean setItemsSelected(Iterable<String> ids, boolean selected) {
         return mDelegate.setItemsSelected(ids, selected);
     }
 
     @Override
-    public void clearSelection() {
-        mDelegate.clearSelection();
+    public boolean clearSelection() {
+        return mDelegate.clearSelection();
     }
 
     @Override
@@ -129,50 +116,59 @@ public final class DocsSelectionHelper extends SelectionHelper {
     }
 
     @Override
-    public void extendProvisionalRange(int pos) {
-        mDelegate.extendProvisionalRange(pos);
+    public void endRange() {
+        mDelegate.endRange();
     }
 
     @Override
-    public void clearProvisionalSelection() {
-        mDelegate.clearProvisionalSelection();
+    public boolean isRangeActive() {
+        return mDelegate.isRangeActive();
     }
 
     @Override
-    public void setProvisionalSelection(Set<String> newSelection) {
-        mDelegate.setProvisionalSelection(newSelection);
+    public void anchorRange(int position) {
+        mDelegate.anchorRange(position);
     }
 
     @Override
-    public void mergeProvisionalSelection() {
-        mDelegate.mergeProvisionalSelection();
+    public void onSaveInstanceState(Bundle state) {
+        mDelegate.onSaveInstanceState(state);
     }
 
     @Override
-    public void endRange() {
-        mDelegate.endRange();
+    public void onRestoreInstanceState(Bundle state) {
+        mDelegate.onRestoreInstanceState(state);
     }
 
+    // Below overridden protected methods are not used for delegation. These empty implementations
+    // are just required by abstract declaration of parent class.
     @Override
-    public boolean isRangeActive() {
-        return mDelegate.isRangeActive();
+    protected void restoreSelection(Selection<String> selection) {
     }
 
     @Override
-    public void anchorRange(int position) {
-        mDelegate.anchorRange(position);
+    protected AdapterDataObserver getAdapterDataObserver() {
+        return null;
+    }
+
+    @Override
+    protected void extendProvisionalRange(int position) {
     }
 
-    public static DocsSelectionHelper createMultiSelect() {
-        return new DocsSelectionHelper(
-                DelegateFactory.INSTANCE,
-                DefaultSelectionHelper.MODE_MULTIPLE);
+    @Override
+    protected void setProvisionalSelection(Set<String> newSelection) {
     }
 
-    public static DocsSelectionHelper createSingleSelect() {
-        return new DocsSelectionHelper(
-                DelegateFactory.INSTANCE,
-                DefaultSelectionHelper.MODE_SINGLE);
+    @Override
+    protected void clearProvisionalSelection() {
+    }
+
+    @Override
+    protected void mergeProvisionalSelection() {
+    }
+
+    public static DocsSelectionHelper create() {
+        return new DocsSelectionHelper(DelegateFactory.INSTANCE);
     }
 
     /**
@@ -183,107 +179,30 @@ public final class DocsSelectionHelper extends SelectionHelper {
     static class DelegateFactory {
         static final DelegateFactory INSTANCE = new DelegateFactory();
 
-        SelectionHelper create(
-                @SelectionMode int mode,
-                RecyclerView.Adapter<?> adapter,
-                StableIdProvider stableIds,
-                SelectionPredicate canSetState) {
-
-            return new DefaultSelectionHelper(mode, adapter, stableIds, canSetState);
+        SelectionTracker<String> create(SelectionTracker<String> selectionTracker) {
+            return selectionTracker;
         }
     }
 
     /**
-     * A dummy SelectHelper used by DocsSelectionHelper before a real
-     * SelectionHelper has been initialized by DirectoryFragment.
+     * Facilitates the use of ItemDetailsLookup.
      */
-    private static final class DummySelectionHelper extends SelectionHelper {
-
-        @Override
-        public void addObserver(SelectionObserver listener) {
-        }
-
-        @Override
-        public boolean hasSelection() {
-            return false;
-        }
-
-        @Override
-        public Selection getSelection() {
-            return new MutableSelection();
-        }
-
-        @Override
-        public void copySelection(Selection dest) {
-        }
+    public static abstract class DocDetailsLookup extends ItemDetailsLookup<String> {
 
+        // Override as public for usages in other packages.
         @Override
-        public boolean isSelected(String id) {
-            return false;
-        }
-
-        @VisibleForTesting
-        public void replaceSelection(Iterable<String> ids) {
-        }
-
-        @Override
-        public void restoreSelection(Selection other) {
-        }
-
-        @Override
-        public boolean setItemsSelected(Iterable<String> ids, boolean selected) {
-            return false;
-        }
-
-        @Override
-        public void clearSelection() {
-        }
-
-        @Override
-        public boolean select(String modelId) {
-            return false;
-        }
-
-        @Override
-        public boolean deselect(String modelId) {
-            return false;
-        }
-
-        @Override
-        public void startRange(int pos) {
-        }
-
-        @Override
-        public void extendRange(int pos) {
-        }
-
-        @Override
-        public void extendProvisionalRange(int pos) {
-        }
-
-        @Override
-        public void clearProvisionalSelection() {
-        }
-
-        @Override
-        public void setProvisionalSelection(Set<String> newSelection) {
-        }
-
-        @Override
-        public void mergeProvisionalSelection() {
-        }
-
-        @Override
-        public void endRange() {
+        public boolean overItemWithSelectionKey(MotionEvent e) {
+            return super.overItemWithSelectionKey(e);
         }
+    }
 
-        @Override
-        public boolean isRangeActive() {
-            return false;
-        }
+    /**
+     * Facilitates the use of stable ids.
+     */
+    public static abstract class StableIdProvider extends ItemKeyProvider<String> {
 
-        @Override
-        public void anchorRange(int position) {
+        protected StableIdProvider() {
+            super(ItemKeyProvider.SCOPE_MAPPED);
         }
     }
 }
diff --git a/src/com/android/documentsui/DragHoverListener.java b/src/com/android/documentsui/DragHoverListener.java
index d26f7caa9..9994de5f3 100644
--- a/src/com/android/documentsui/DragHoverListener.java
+++ b/src/com/android/documentsui/DragHoverListener.java
@@ -24,9 +24,8 @@ import android.view.View.OnDragListener;
 import android.widget.AbsListView;
 
 import com.android.documentsui.ItemDragListener.DragHost;
-import com.android.documentsui.selection.ViewAutoScroller;
-import com.android.documentsui.selection.ViewAutoScroller.ScrollHost;
-import com.android.documentsui.selection.ViewAutoScroller.ScrollerCallbacks;
+import com.android.documentsui.ViewAutoScroller.ScrollHost;
+import com.android.documentsui.ViewAutoScroller.ScrollerCallbacks;
 
 import java.util.function.BooleanSupplier;
 import java.util.function.IntConsumer;
diff --git a/src/com/android/documentsui/DummySelectionTracker.java b/src/com/android/documentsui/DummySelectionTracker.java
new file mode 100644
index 000000000..49b9ad918
--- /dev/null
+++ b/src/com/android/documentsui/DummySelectionTracker.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.documentsui;
+
+import android.os.Bundle;
+
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.Selection;
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.widget.RecyclerView.AdapterDataObserver;
+
+import java.util.Set;
+
+/**
+ * A dummy SelectionTracker used by DocsSelectionHelper before a real SelectionTracker has been
+ * initialized by DirectoryFragment.
+ */
+public class DummySelectionTracker<K> extends SelectionTracker<K> {
+
+    @Override
+    public void addObserver(SelectionObserver observer) {
+    }
+
+    @Override
+    public boolean hasSelection() {
+        return false;
+    }
+
+    @Override
+    public Selection<K> getSelection() {
+        return new MutableSelection<K>();
+    }
+
+    @Override
+    public void copySelection(MutableSelection<K> dest) {
+    }
+
+    @Override
+    public boolean isSelected(K key) {
+        return false;
+    }
+
+    @Override
+    public void restoreSelection(Selection<K> selection) {
+    }
+
+    @Override
+    public boolean clearSelection() {
+        return false;
+    }
+
+    @Override
+    public boolean setItemsSelected(Iterable<K> keys, boolean selected) {
+        return false;
+    }
+
+    @Override
+    public boolean select(K key) {
+        return false;
+    }
+
+    @Override
+    public boolean deselect(K key) {
+        return false;
+    }
+
+    @Override
+    protected AdapterDataObserver getAdapterDataObserver() {
+        return null;
+    }
+
+    @Override
+    public void startRange(int position) {
+    }
+
+    @Override
+    public void extendRange(int position) {
+    }
+
+    @Override
+    public void endRange() {
+    }
+
+    @Override
+    public boolean isRangeActive() {
+        return false;
+    }
+
+    @Override
+    public void anchorRange(int position) {
+    }
+
+    @Override
+    public void extendProvisionalRange(int position) {
+    }
+
+    @Override
+    public void setProvisionalSelection(Set<K> newSelection) {
+    }
+
+    @Override
+    public void clearProvisionalSelection() {
+    }
+
+    @Override
+    public void mergeProvisionalSelection() {
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle state) {
+    }
+
+    @Override
+    public void onRestoreInstanceState(Bundle state) {
+    }
+
+}
diff --git a/src/com/android/documentsui/FocusManager.java b/src/com/android/documentsui/FocusManager.java
index 5fe732684..7a228ffe3 100644
--- a/src/com/android/documentsui/FocusManager.java
+++ b/src/com/android/documentsui/FocusManager.java
@@ -27,8 +27,6 @@ import android.os.Handler;
 import android.os.Looper;
 import android.os.SystemClock;
 import android.provider.DocumentsContract.Document;
-import androidx.recyclerview.widget.GridLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
 import android.text.Editable;
 import android.text.Spannable;
 import android.text.method.KeyListener;
@@ -40,6 +38,13 @@ import android.view.KeyEvent;
 import android.view.View;
 import android.widget.TextView;
 
+import androidx.recyclerview.selection.FocusDelegate;
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.widget.GridLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.android.documentsui.Model.Update;
 import com.android.documentsui.base.EventListener;
 import com.android.documentsui.base.Events;
 import com.android.documentsui.base.Features;
@@ -47,21 +52,22 @@ import com.android.documentsui.base.Procedure;
 import com.android.documentsui.dirlist.DocumentHolder;
 import com.android.documentsui.dirlist.DocumentsAdapter;
 import com.android.documentsui.dirlist.FocusHandler;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.Model.Update;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Timer;
 import java.util.TimerTask;
 
-public final class FocusManager implements FocusHandler {
+/**
+ * The implementation to handle focus and keyboard driven navigation.
+ */
+public final class FocusManager extends FocusDelegate<String> implements FocusHandler {
     private static final String TAG = "FocusManager";
 
     private final ContentScope mScope = new ContentScope();
 
     private final Features mFeatures;
-    private final SelectionHelper mSelectionMgr;
+    private final SelectionTracker<String> mSelectionMgr;
     private final DrawerController mDrawer;
     private final Procedure mRootsFocuser;
     private final TitleSearchHelper mSearchHelper;
@@ -70,7 +76,7 @@ public final class FocusManager implements FocusHandler {
 
     public FocusManager(
             Features features,
-            SelectionHelper selectionMgr,
+            SelectionTracker<String> selectionMgr,
             DrawerController drawer,
             Procedure rootsFocuser,
             @ColorRes int color) {
@@ -205,7 +211,12 @@ public final class FocusManager implements FocusHandler {
     }
 
     @Override
-    public int getFocusPosition() {
+    public void focusItem(ItemDetails<String> item) {
+        focusDocument(item.getSelectionKey());
+    }
+
+    @Override
+    public int getFocusedPosition() {
         return mScope.lastFocusPosition;
     }
 
diff --git a/src/com/android/documentsui/Injector.java b/src/com/android/documentsui/Injector.java
index ea4dd90a7..0fc3670f0 100644
--- a/src/com/android/documentsui/Injector.java
+++ b/src/com/android/documentsui/Injector.java
@@ -18,9 +18,11 @@ package com.android.documentsui;
 import static java.lang.annotation.ElementType.FIELD;
 import static java.lang.annotation.RetentionPolicy.SOURCE;
 
+import android.view.MenuItem;
+
 import androidx.annotation.Nullable;
+import androidx.recyclerview.selection.SelectionTracker;
 import androidx.recyclerview.widget.RecyclerView;
-import android.view.MenuItem;
 
 import com.android.documentsui.MenuManager.SelectionDetails;
 import com.android.documentsui.base.DebugHelper;
@@ -28,12 +30,8 @@ import com.android.documentsui.base.EventHandler;
 import com.android.documentsui.base.Features;
 import com.android.documentsui.base.Lookup;
 import com.android.documentsui.base.RootInfo;
-import com.android.documentsui.dirlist.DocsStableIdProvider;
-import com.android.documentsui.dirlist.DocumentsAdapter;
 import com.android.documentsui.prefs.ScopedPreferences;
 import com.android.documentsui.queries.SearchViewManager;
-import com.android.documentsui.selection.ContentLock;
-import com.android.documentsui.selection.SelectionHelper;
 import com.android.documentsui.ui.DialogController;
 import com.android.documentsui.ui.MessageBuilder;
 import androidx.annotation.VisibleForTesting;
@@ -120,9 +118,8 @@ public class Injector<T extends ActionHandler> {
         return focusManager.reset(view, model);
     }
 
-    public SelectionHelper getSelectionManager(
-            DocumentsAdapter adapter, SelectionHelper.SelectionPredicate canSetState) {
-        return selectionMgr.reset(adapter, new DocsStableIdProvider(adapter), canSetState);
+    public void updateSharedSelectionTracker(SelectionTracker<String> selectionTracker) {
+        selectionMgr.reset(selectionTracker);
     }
 
     public final ActionModeController getActionModeController(
diff --git a/src/com/android/documentsui/Model.java b/src/com/android/documentsui/Model.java
index f02c324a1..7141ab90e 100644
--- a/src/com/android/documentsui/Model.java
+++ b/src/com/android/documentsui/Model.java
@@ -28,16 +28,17 @@ import android.net.Uri;
 import android.os.Bundle;
 import android.provider.DocumentsContract;
 import android.provider.DocumentsContract.Document;
+import android.util.Log;
+
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
-import android.util.Log;
+import androidx.recyclerview.selection.Selection;
 
 import com.android.documentsui.base.DocumentFilters;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.EventListener;
 import com.android.documentsui.base.Features;
 import com.android.documentsui.roots.RootCursorWrapper;
-import com.android.documentsui.selection.Selection;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -73,7 +74,7 @@ public class Model {
     private @Nullable Cursor mCursor;
     private int mCursorCount;
     private String mIds[] = new String[0];
-    private Set<Selection> mDocumentsToBeDeleted = new HashSet<>();
+    private Set<Selection<String>> mDocumentsToBeDeleted = new HashSet<>();
 
     public Model(Features features) {
         mFeatures = features;
@@ -142,7 +143,7 @@ public class Model {
         notifyUpdateListeners();
     }
 
-    public void markDocumentsToBeDeleted(Selection selection) {
+    public void markDocumentsToBeDeleted(Selection<String> selection) {
         if (mDocumentsToBeDeleted.contains(selection)) {
             return;
         }
@@ -151,7 +152,7 @@ public class Model {
         notifyUpdateListeners();
     }
 
-    public void restoreDocumentsToBeDeleted(Selection selection) {
+    public void restoreDocumentsToBeDeleted(Selection<String> selection) {
         if (!mDocumentsToBeDeleted.contains(selection)) {
             return;
         }
@@ -161,7 +162,7 @@ public class Model {
     }
 
     private boolean isDocumentToBeDeleted(String id) {
-        for (Selection s : mDocumentsToBeDeleted) {
+        for (Selection<String> s : mDocumentsToBeDeleted) {
             if (s.contains(id)) {
                 return true;
             }
@@ -170,8 +171,8 @@ public class Model {
     }
 
     private void updateDocumentsToBeDeleted() {
-        for (Iterator<Selection> i = mDocumentsToBeDeleted.iterator(); i.hasNext();) {
-            Selection selection = i.next();
+        for (Iterator<Selection<String>> i = mDocumentsToBeDeleted.iterator(); i.hasNext();) {
+            Selection<String> selection = i.next();
             for (String id : selection) {
                 if (!mPositions.containsKey(id)) {
                     i.remove();
@@ -183,7 +184,7 @@ public class Model {
 
     private int getDocumentsToBeDeletedCount() {
         int count = 0;
-        for (Selection s : mDocumentsToBeDeleted) {
+        for (Selection<String> s : mDocumentsToBeDeleted) {
             count += s.size();
         }
         return count;
@@ -258,7 +259,7 @@ public class Model {
         return mIsLoading;
     }
 
-    public List<DocumentInfo> getDocuments(Selection selection) {
+    public List<DocumentInfo> getDocuments(Selection<String> selection) {
         return loadDocuments(selection, DocumentFilters.ANY);
     }
 
@@ -269,7 +270,7 @@ public class Model {
                 : DocumentInfo.fromDirectoryCursor(cursor);
     }
 
-    public List<DocumentInfo> loadDocuments(Selection selection, Predicate<Cursor> filter) {
+    public List<DocumentInfo> loadDocuments(Selection<String> selection, Predicate<Cursor> filter) {
         final int size = (selection != null) ? selection.size() : 0;
 
         final List<DocumentInfo> docs =  new ArrayList<>(size);
@@ -283,7 +284,7 @@ public class Model {
         return docs;
     }
 
-    public boolean hasDocuments(Selection selection, Predicate<Cursor> filter) {
+    public boolean hasDocuments(Selection<String> selection, Predicate<Cursor> filter) {
         for (String modelId: selection) {
             if (loadDocument(modelId, filter) != null) {
                 return true;
diff --git a/src/com/android/documentsui/SharedInputHandler.java b/src/com/android/documentsui/SharedInputHandler.java
index 8d39204cd..b9a5b92c3 100644
--- a/src/com/android/documentsui/SharedInputHandler.java
+++ b/src/com/android/documentsui/SharedInputHandler.java
@@ -20,12 +20,16 @@ import static com.android.documentsui.base.SharedMinimal.DEBUG;
 import android.util.Log;
 import android.view.KeyEvent;
 
+import androidx.recyclerview.selection.SelectionTracker;
+
 import com.android.documentsui.base.Events;
 import com.android.documentsui.base.Features;
 import com.android.documentsui.base.Procedure;
 import com.android.documentsui.dirlist.FocusHandler;
-import com.android.documentsui.selection.SelectionHelper;
 
+/**
+ * Handle common input events.
+ */
 public class SharedInputHandler {
 
     private static final String TAG = "SharedInputHandler";
@@ -34,12 +38,12 @@ public class SharedInputHandler {
     private final Procedure mSearchCanceler;
     private final Procedure mDirPopper;
     private final Features mFeatures;
-    private final SelectionHelper mSelectionMgr;
+    private final SelectionTracker<String> mSelectionMgr;
     private final DrawerController mDrawer;
 
     public SharedInputHandler(
             FocusHandler focusHandler,
-            SelectionHelper selectionMgr,
+            SelectionTracker<String> selectionMgr,
             Procedure searchCanceler,
             Procedure dirPopper,
             Features features,
diff --git a/src/com/android/documentsui/selection/ViewAutoScroller.java b/src/com/android/documentsui/ViewAutoScroller.java
index b77176c01..f7b062e18 100644
--- a/src/com/android/documentsui/selection/ViewAutoScroller.java
+++ b/src/com/android/documentsui/ViewAutoScroller.java
@@ -14,16 +14,15 @@
  * limitations under the License.
  */
 
-package com.android.documentsui.selection;
+package com.android.documentsui;
 
 import android.graphics.Point;
 
 /**
  * Provides auto-scrolling upon request when user's interaction with the application
- * introduces a natural intent to scroll. Used by BandController, GestureSelector,
- * and DragHoverListener to allow auto scrolling when user either does band selection,
- * attempting to drag and drop files to somewhere off the current screen, or trying to motion select
- * past top/bottom of the screen.
+ * introduces a natural intent to scroll. Used by DragHoverListener to allow auto scrolling
+ * when user either does band selection, attempting to drag and drop files to somewhere off
+ * the current screen, or trying to motion select past top/bottom of the screen.
  */
 public final class ViewAutoScroller implements Runnable {
 
diff --git a/src/com/android/documentsui/base/Events.java b/src/com/android/documentsui/base/Events.java
index c38f1a4c6..1e6be6c3c 100644
--- a/src/com/android/documentsui/base/Events.java
+++ b/src/com/android/documentsui/base/Events.java
@@ -16,7 +16,6 @@
 
 package com.android.documentsui.base;
 
-import android.graphics.Point;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 
@@ -29,10 +28,6 @@ public final class Events {
         return e.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE;
     }
 
-    public static boolean isActionMove(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_MOVE;
-    }
-
     public static boolean isActionDown(MotionEvent e) {
         return e.getActionMasked() == MotionEvent.ACTION_DOWN;
     }
@@ -49,22 +44,6 @@ public final class Events {
         return e.getActionMasked() == MotionEvent.ACTION_POINTER_UP;
     }
 
-    public static boolean isActionCancel(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_CANCEL;
-    }
-
-    public static boolean isPrimaryButtonPressed(MotionEvent e) {
-        return e.isButtonPressed(MotionEvent.BUTTON_PRIMARY);
-    }
-
-    public static boolean isSecondaryButtonPressed(MotionEvent e) {
-        return e.isButtonPressed(MotionEvent.BUTTON_SECONDARY);
-    }
-
-    public static boolean isTertiaryButtonPressed(MotionEvent e) {
-        return e.isButtonPressed(MotionEvent.BUTTON_TERTIARY);
-    }
-
     public static boolean isCtrlKeyPressed(MotionEvent e) {
         return hasBit(e.getMetaState(), KeyEvent.META_CTRL_ON);
     }
@@ -77,20 +56,10 @@ public final class Events {
         return hasBit(e.getMetaState(), KeyEvent.META_SHIFT_ON);
     }
 
-    public static boolean isTouchpadScroll(MotionEvent e) {
-        // Touchpad inputs are treated as mouse inputs, and when scrolling, there are no buttons
-        // returned.
-        return isMouseEvent(e) && isActionMove(e) && e.getButtonState() == 0;
-    }
-
     private static boolean hasBit(int metaState, int bit) {
         return (metaState & bit) != 0;
     }
 
-    public static Point getOrigin(MotionEvent e) {
-        return new Point((int) e.getX(), (int) e.getY());
-    }
-
     /**
      * @return true if keyCode is a known navigation code (e.g. up, down, home).
      */
@@ -109,15 +78,4 @@ public final class Events {
                 return false;
         }
     }
-
-    /**
-     * Returns true if the event is a mouse drag event.
-     * @param e
-     * @return
-     */
-    public static boolean isMouseDragEvent(MotionEvent e) {
-        return isMouseEvent(e)
-                && isActionMove(e)
-                && isPrimaryButtonPressed(e);
-    }
 }
diff --git a/src/com/android/documentsui/clipping/DocumentClipper.java b/src/com/android/documentsui/clipping/DocumentClipper.java
index dbb84fca3..fe85e27e3 100644
--- a/src/com/android/documentsui/clipping/DocumentClipper.java
+++ b/src/com/android/documentsui/clipping/DocumentClipper.java
@@ -20,12 +20,11 @@ import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
 import android.net.Uri;
-import androidx.annotation.Nullable;
+
+import androidx.recyclerview.selection.Selection;
 
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.DocumentStack;
-import com.android.documentsui.base.RootInfo;
-import com.android.documentsui.selection.Selection;
 import com.android.documentsui.services.FileOperationService.OpType;
 import com.android.documentsui.services.FileOperations;
 
@@ -47,7 +46,7 @@ public interface DocumentClipper {
      * Returns {@link ClipData} representing the selection, or null if selection is empty,
      * or cannot be converted.
      */
-    ClipData getClipDataForDocuments(Function<String, Uri> uriBuilder, Selection selection,
+    ClipData getClipDataForDocuments(Function<String, Uri> uriBuilder, Selection<String> selection,
             @OpType int opType);
 
     /**
@@ -63,13 +62,13 @@ public interface DocumentClipper {
     /**
      * Puts {@code ClipData} in a primary clipboard, describing a copy operation
      */
-    void clipDocumentsForCopy(Function<String, Uri> uriBuilder, Selection selection);
+    void clipDocumentsForCopy(Function<String, Uri> uriBuilder, Selection<String> selection);
 
     /**
      *  Puts {@Code ClipData} in a primary clipboard, describing a cut operation
      */
     void clipDocumentsForCut(
-            Function<String, Uri> uriBuilder, Selection selection, DocumentInfo parent);
+            Function<String, Uri> uriBuilder, Selection<String> selection, DocumentInfo parent);
 
     /**
      * Copies documents from clipboard. It's the same as {@link #copyFromClipData} with clipData
diff --git a/src/com/android/documentsui/clipping/RuntimeDocumentClipper.java b/src/com/android/documentsui/clipping/RuntimeDocumentClipper.java
index 64311f349..1c5804c57 100644
--- a/src/com/android/documentsui/clipping/RuntimeDocumentClipper.java
+++ b/src/com/android/documentsui/clipping/RuntimeDocumentClipper.java
@@ -24,15 +24,15 @@ import android.content.Context;
 import android.net.Uri;
 import android.os.PersistableBundle;
 import android.provider.DocumentsContract;
-import androidx.annotation.Nullable;
 import android.util.Log;
 
+import androidx.annotation.Nullable;
+import androidx.recyclerview.selection.Selection;
+
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.DocumentStack;
 import com.android.documentsui.base.Features;
-import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.base.Shared;
-import com.android.documentsui.selection.Selection;
 import com.android.documentsui.services.FileOperation;
 import com.android.documentsui.services.FileOperationService;
 import com.android.documentsui.services.FileOperationService.OpType;
@@ -90,7 +90,7 @@ final class RuntimeDocumentClipper implements DocumentClipper {
 
     @Override
     public ClipData getClipDataForDocuments(
-        Function<String, Uri> uriBuilder, Selection selection, @OpType int opType) {
+        Function<String, Uri> uriBuilder, Selection<String> selection, @OpType int opType) {
 
         assert(selection != null);
 
@@ -190,7 +190,8 @@ final class RuntimeDocumentClipper implements DocumentClipper {
     }
 
     @Override
-    public void clipDocumentsForCopy(Function<String, Uri> uriBuilder, Selection selection) {
+    public void clipDocumentsForCopy(
+            Function<String, Uri> uriBuilder, Selection<String> selection) {
         ClipData data =
                 getClipDataForDocuments(uriBuilder, selection, FileOperationService.OPERATION_COPY);
         assert(data != null);
@@ -200,7 +201,7 @@ final class RuntimeDocumentClipper implements DocumentClipper {
 
     @Override
     public void clipDocumentsForCut(
-            Function<String, Uri> uriBuilder, Selection selection, DocumentInfo parent) {
+            Function<String, Uri> uriBuilder, Selection<String> selection, DocumentInfo parent) {
         assert(!selection.isEmpty());
         assert(parent.derivedUri != null);
 
diff --git a/src/com/android/documentsui/clipping/UrisSupplier.java b/src/com/android/documentsui/clipping/UrisSupplier.java
index fd4d0e653..6679347d6 100644
--- a/src/com/android/documentsui/clipping/UrisSupplier.java
+++ b/src/com/android/documentsui/clipping/UrisSupplier.java
@@ -25,12 +25,13 @@ import android.net.Uri;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.os.PersistableBundle;
-import androidx.annotation.VisibleForTesting;
 import android.util.Log;
 
+import androidx.annotation.VisibleForTesting;
+import androidx.recyclerview.selection.Selection;
+
 import com.android.documentsui.DocumentsApplication;
 import com.android.documentsui.base.Shared;
-import com.android.documentsui.selection.Selection;
 import com.android.documentsui.services.FileOperation;
 
 import java.io.File;
@@ -82,7 +83,7 @@ public abstract class UrisSupplier implements Parcelable {
     }
 
     public static UrisSupplier create(
-            Selection selection, Function<String, Uri> uriBuilder, ClipStore storage)
+            Selection<String> selection, Function<String, Uri> uriBuilder, ClipStore storage)
             throws IOException {
 
         List<Uri> uris = new ArrayList<>(selection.size());
diff --git a/src/com/android/documentsui/dirlist/DirectoryFragment.java b/src/com/android/documentsui/dirlist/DirectoryFragment.java
index 2cd150c37..e3b429b09 100644
--- a/src/com/android/documentsui/dirlist/DirectoryFragment.java
+++ b/src/com/android/documentsui/dirlist/DirectoryFragment.java
@@ -34,23 +34,14 @@ import android.content.Context;
 import android.content.Intent;
 import android.database.Cursor;
 import android.net.Uri;
-import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Parcelable;
 import android.provider.DocumentsContract;
 import android.provider.DocumentsContract.Document;
-import androidx.annotation.Nullable;
-import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
-import androidx.recyclerview.widget.GridLayoutManager;
-import androidx.recyclerview.widget.GridLayoutManager.SpanSizeLookup;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.RecyclerListener;
-import androidx.recyclerview.widget.RecyclerView.ViewHolder;
 import android.util.Log;
 import android.util.SparseArray;
 import android.view.ContextMenu;
-import android.view.GestureDetector;
 import android.view.LayoutInflater;
 import android.view.MenuInflater;
 import android.view.MenuItem;
@@ -59,10 +50,25 @@ import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ImageView;
 
+import androidx.annotation.Nullable;
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.Selection;
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.selection.StorageStrategy;
+import androidx.recyclerview.selection.SelectionTracker.SelectionPredicate;
+import androidx.recyclerview.widget.GridLayoutManager;
+import androidx.recyclerview.widget.GridLayoutManager.SpanSizeLookup;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.recyclerview.widget.RecyclerView.RecyclerListener;
+import androidx.recyclerview.widget.RecyclerView.ViewHolder;
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+
 import com.android.documentsui.ActionHandler;
 import com.android.documentsui.ActionModeController;
 import com.android.documentsui.BaseActivity;
-import com.android.documentsui.BaseActivity.RetainedState;
+import com.android.documentsui.ContentLock;
+import com.android.documentsui.DocsSelectionHelper.DocDetailsLookup;
 import com.android.documentsui.DocumentsApplication;
 import com.android.documentsui.DragHoverListener;
 import com.android.documentsui.FocusManager;
@@ -87,20 +93,6 @@ import com.android.documentsui.clipping.DocumentClipper;
 import com.android.documentsui.clipping.UrisSupplier;
 import com.android.documentsui.dirlist.AnimationView.AnimationType;
 import com.android.documentsui.picker.PickActivity;
-import com.android.documentsui.selection.BandSelectionHelper;
-import com.android.documentsui.selection.ContentLock;
-import com.android.documentsui.selection.DefaultBandHost;
-import com.android.documentsui.selection.DefaultBandPredicate;
-import com.android.documentsui.selection.GestureRouter;
-import com.android.documentsui.selection.GestureSelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup;
-import com.android.documentsui.selection.MotionInputHandler;
-import com.android.documentsui.selection.MouseInputHandler;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-import com.android.documentsui.selection.TouchEventRouter;
-import com.android.documentsui.selection.TouchInputHandler;
 import com.android.documentsui.services.FileOperation;
 import com.android.documentsui.services.FileOperationService;
 import com.android.documentsui.services.FileOperationService.OpType;
@@ -129,7 +121,6 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
     public static final int REQUEST_COPY_DESTINATION = 1;
 
     static final String TAG = "DirectoryFragment";
-    private static final int LOADER_ID = 42;
 
     private static final int CACHE_EVICT_LIMIT = 100;
     private static final int REFRESH_SPINNER_TIMEOUT = 500;
@@ -147,7 +138,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
 
     @Injected
     @ContentScoped
-    private SelectionHelper mSelectionMgr;
+    private SelectionTracker<String> mSelectionMgr;
 
     @Injected
     @ContentScoped
@@ -161,10 +152,9 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
     @ContentScoped
     private ActionModeController mActionModeController;
 
-    private ItemDetailsLookup mDetailsLookup;
+    private DocDetailsLookup mDetailsLookup;
     private SelectionMetadata mSelectionMetadata;
     private KeyInputHandler mKeyListener;
-    private @Nullable BandSelectionHelper mBandSelector;
     private @Nullable DragHoverListener mDragHoverListener;
     private IconHelper mIconHelper;
     private SwipeRefreshLayout mRefreshLayout;
@@ -181,14 +171,12 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
 
     private DirectoryState mLocalState;
 
-    // Blocks loading/reloading of content while user is actively making selection.
-    private ContentLock mContentLock = new ContentLock();
-
-    private Runnable mBandSelectStartedCallback;
-
     // Note, we use !null to indicate that selection was restored (from rotation).
     // So don't fiddle with this field unless you've got the bigger picture in mind.
-    private @Nullable Selection mRestoredSelection = null;
+    private @Nullable Bundle mRestoredState;
+
+    // Blocks loading/reloading of content while user is actively making selection.
+    private ContentLock mContentLock = new ContentLock();
 
     private SortModel.UpdateListener mSortListener = (model, updateType) -> {
         // Only when sort order has changed do we need to trigger another loading.
@@ -223,6 +211,9 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         mRecView.setItemAnimator(new DirectoryItemAnimator(mActivity));
 
         mInjector = mActivity.getInjector();
+        // Initially, this selection tracker (delegator) uses a dummy implementation, so it must be
+        // updated (reset) when necessary things are ready.
+        mSelectionMgr = mInjector.selectionMgr;
         mModel = mInjector.getModel();
         mModel.reset();
 
@@ -234,7 +225,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
                     new DragHost<>(
                             mActivity,
                             DocumentsApplication.getDragAndDropManager(mActivity),
-                            mInjector.selectionMgr,
+                            mSelectionMgr,
                             mInjector.actions,
                             mActivity.getDisplayState(),
                             mInjector.dialogs,
@@ -267,10 +258,6 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         mModel.removeUpdateListener(mModelUpdateListener);
         mModel.removeUpdateListener(mAdapter.getModelUpdateListener());
 
-        if (mBandSelector != null) {
-            mBandSelector.removeOnBandStartedListener(mBandSelectStartedCallback);
-        }
-
         super.onDestroyView();
     }
 
@@ -283,17 +270,12 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         // Read arguments when object created for the first time.
         // Restore state if fragment recreated.
         Bundle args = savedInstanceState == null ? getArguments() : savedInstanceState;
+        mRestoredState = args;
 
         mLocalState = new DirectoryState();
         mLocalState.restore(args);
-
-        // Restore any selection we may have squirreled away in retained state.
-        @Nullable RetainedState retained = mActivity.getRetainedState();
-        if (retained != null && retained.hasSelection()) {
-            // We claim the selection for ourselves and null it out once used
-            // so we don't have a rando selection hanging around in RetainedState.
-            mRestoredSelection = retained.selection;
-            retained.selection = null;
+        if (mLocalState.mSelectionId == null) {
+            mLocalState.mSelectionId = Integer.toHexString(System.identityHashCode(mRecView));
         }
 
         mIconHelper = new IconHelper(mActivity, MODE_GRID);
@@ -322,10 +304,9 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         mModel.addUpdateListener(mAdapter.getModelUpdateListener());
         mModel.addUpdateListener(mModelUpdateListener);
 
-        SelectionPredicate selectionPredicate =
+        SelectionPredicate<String> selectionPredicate =
                 new DocsSelectionPredicate(mInjector.config, mState, mModel, mRecView);
 
-        mSelectionMgr = mInjector.getSelectionManager(mAdapter, selectionPredicate);
         mFocusManager = mInjector.getFocusManager(mRecView, mModel);
         mActions = mInjector.getActionHandler(mContentLock);
 
@@ -333,26 +314,8 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
                 new AccessibilityEventRouter(mRecView,
                         (View child) -> onAccessibilityClick(child)));
         mSelectionMetadata = new SelectionMetadata(mModel::getItem);
-        mSelectionMgr.addObserver(mSelectionMetadata);
         mDetailsLookup = new DocsItemDetailsLookup(mRecView);
 
-        GestureSelectionHelper gestureHelper = GestureSelectionHelper.create(
-                mSelectionMgr, mRecView, mContentLock, mDetailsLookup);
-
-        if (mState.allowMultiple) {
-            mBandSelector = new BandSelectionHelper(
-                    new DefaultBandHost(mRecView, R.drawable.band_select_overlay),
-                    mAdapter,
-                    new DocsStableIdProvider(mAdapter),
-                    mSelectionMgr,
-                    selectionPredicate,
-                    new DefaultBandPredicate(mDetailsLookup),
-                    mContentLock);
-
-            mBandSelectStartedCallback = mFocusManager::clearFocus;
-            mBandSelector.addOnBandStartedListener(mBandSelectStartedCallback);
-        }
-
         DragStartListener dragStartListener = mInjector.config.dragAndDropEnabled()
                 ? DragStartListener.create(
                         mIconHelper,
@@ -360,12 +323,33 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
                         mSelectionMgr,
                         mSelectionMetadata,
                         mState,
-                        mDetailsLookup,
                         this::getModelId,
                         mRecView::findChildViewUnder,
                         DocumentsApplication.getDragAndDropManager(mActivity))
                 : DragStartListener.DUMMY;
 
+        {
+            // Limiting the scope of the localTracker so nobody uses it.
+            // This block initializes/updates the global SelectionTracker held in mSelectionMgr.
+            SelectionTracker<String> localTracker = new SelectionTracker.Builder<>(
+                    mLocalState.mSelectionId,
+                    mRecView,
+                    new DocsStableIdProvider(mAdapter),
+                    mDetailsLookup,
+                    StorageStrategy.createStringStorage())
+                            .withBandOverlay(R.drawable.band_select_overlay)
+                            .withFocusDelegate(mFocusManager)
+                            .withOnDragInitiatedListener(dragStartListener::onDragEvent)
+                            .withOnContextClickListener(this::onContextMenuClick)
+                            .withOnItemActivatedListener(this::onItemActivated)
+                            .withOperationMonitor(mContentLock.getMonitor())
+                            .withSelectionPredicate(selectionPredicate)
+                            .build();
+            mInjector.updateSharedSelectionTracker(localTracker);
+        }
+
+        mSelectionMgr.addObserver(mSelectionMetadata);
+
         // Construction of the input handlers is non trivial, so to keep logic clear,
         // and code flexible, and DirectoryFragment small, the construction has been
         // moved off into a separate class.
@@ -373,19 +357,8 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
                 mActions,
                 mSelectionMgr,
                 selectionPredicate,
-                mDetailsLookup,
                 mFocusManager,
-                mRecView,
-                mState);
-
-        MouseInputHandler mouseHandler =
-                handlers.createMouseHandler(this::onContextMenuClick);
-
-        TouchInputHandler touchHandler =
-                handlers.createTouchHandler(gestureHelper, dragStartListener);
-
-        GestureRouter<MotionInputHandler> gestureRouter = new GestureRouter<>(touchHandler);
-        gestureRouter.register(MotionEvent.TOOL_TYPE_MOUSE, mouseHandler);
+                mRecView);
 
         // This little guy gets added to each Holder, so that we can be notified of key events
         // on RecyclerView items.
@@ -399,17 +372,6 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         new RefreshHelper(mRefreshLayout::setEnabled)
                 .attach(mRecView);
 
-        GestureDetector gestureDetector = new GestureDetector(getContext(), gestureRouter);
-
-        TouchEventRouter eventRouter = new TouchEventRouter(gestureDetector, gestureHelper);
-
-        eventRouter.register(
-                MotionEvent.TOOL_TYPE_MOUSE,
-                new MouseDragEventInterceptor(
-                        mDetailsLookup, dragStartListener::onMouseDragEvent, mBandSelector));
-
-        mRecView.addOnItemTouchListener(eventRouter);
-
         mActionModeController = mInjector.getActionModeController(
                 mSelectionMetadata,
                 this::handleMenuItemClick);
@@ -455,16 +417,12 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         mState.dirConfigs.put(mLocalState.getConfigKey(), container);
     }
 
-    public void retainState(RetainedState state) {
-        state.selection = new Selection();
-        mSelectionMgr.copySelection(state.selection);
-    }
-
     @Override
     public void onSaveInstanceState(Bundle outState) {
         super.onSaveInstanceState(outState);
 
         mLocalState.save(outState);
+        mSelectionMgr.onSaveInstanceState(outState);
     }
 
     @Override
@@ -515,7 +473,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
     // TODO: Move to UserInputHander.
     protected boolean onContextMenuClick(MotionEvent e) {
 
-        if (mDetailsLookup.overStableItem(e)) {
+        if (mDetailsLookup.overItemWithSelectionKey(e)) {
             View childView = mRecView.findChildViewUnder(e.getX(), e.getY());
             ViewHolder holder = mRecView.getChildViewHolder(childView);
 
@@ -530,6 +488,13 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         return true;
     }
 
+    private boolean onItemActivated(ItemDetails<String> item, MotionEvent e) {
+        return mActions.openItem(
+                item,
+                ActionHandler.VIEW_TYPE_PREVIEW,
+                ActionHandler.VIEW_TYPE_REGULAR);
+    }
+
     public void onViewModeChanged() {
         // Mode change is just visual change; no need to kick loader.
         onDisplayStateChanged();
@@ -554,9 +519,6 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         int pad = getDirectoryPadding(mode);
         mRecView.setPadding(pad, pad, pad, pad);
         mRecView.requestLayout();
-        if (mBandSelector != null) {
-            mBandSelector.reset();
-        }
         mIconHelper.setViewMode(mode);
     }
 
@@ -635,7 +597,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
     }
 
     private boolean handleMenuItemClick(MenuItem item) {
-        Selection selection = new Selection();
+        MutableSelection<String> selection = new MutableSelection<>();
         mSelectionMgr.copySelection(selection);
 
         switch (item.getItemId()) {
@@ -780,7 +742,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         }
     }
 
-    private void showChooserForDoc(final Selection selected) {
+    private void showChooserForDoc(final Selection<String> selected) {
         Metrics.logUserAction(getContext(), Metrics.USER_ACTION_OPEN);
 
         assert selected.size() == 1;
@@ -789,7 +751,8 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         mActions.showChooserForDoc(doc);
     }
 
-    private void transferDocuments(final Selection selected, @Nullable DocumentStack destination,
+    private void transferDocuments(
+            final Selection<String> selected, @Nullable DocumentStack destination,
             final @OpType int mode) {
         switch (mode) {
             case FileOperationService.OPERATION_COPY:
@@ -1025,7 +988,6 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         final Bundle args = new Bundle();
         args.putParcelable(Shared.EXTRA_ROOT, root);
         args.putParcelable(Shared.EXTRA_DOC, doc);
-        args.putParcelable(Shared.EXTRA_SELECTION, new Selection());
 
         final FragmentTransaction ft = fm.beginTransaction();
         AnimationView.setupAnimations(ft, anim, args);
@@ -1084,9 +1046,9 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
 
             mAdapter.notifyDataSetChanged();
 
-            if (mRestoredSelection != null) {
-                mSelectionMgr.restoreSelection(mRestoredSelection);
-                mRestoredSelection = null;
+            if (mRestoredState != null) {
+                mSelectionMgr.onRestoreInstanceState(mRestoredState);
+                mRestoredState = null;
             }
 
             // Restore any previous instance state
diff --git a/src/com/android/documentsui/dirlist/DirectoryState.java b/src/com/android/documentsui/dirlist/DirectoryState.java
index b27a4b8f4..30d570c2f 100644
--- a/src/com/android/documentsui/dirlist/DirectoryState.java
+++ b/src/com/android/documentsui/dirlist/DirectoryState.java
@@ -22,8 +22,8 @@ import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.base.Shared;
 import com.android.documentsui.services.FileOperation;
 import com.android.documentsui.services.FileOperationService;
-import com.android.documentsui.sorting.SortModel;
 import com.android.documentsui.sorting.SortDimension.SortDirection;
+import com.android.documentsui.sorting.SortModel;
 
 import javax.annotation.Nullable;
 
@@ -31,6 +31,7 @@ final class DirectoryState {
 
     private static final String EXTRA_SORT_DIMENSION_ID = "sortDimensionId";
     private static final String EXTRA_SORT_DIRECTION = "sortDirection";
+    private static final String EXTRA_SELECTION_ID = "selectionId";
 
     // Null when viewing Recents directory.
     @Nullable DocumentInfo mDocument;
@@ -40,6 +41,10 @@ final class DirectoryState {
     int mLastSortDimensionId = SortModel.SORT_DIMENSION_ID_UNKNOWN;
     @SortDirection int mLastSortDirection;
 
+    // The unique id to identify the selection. It is null when the corresponding
+    // container (fragment/activity) is the first launch.
+    @Nullable String mSelectionId;
+
     private RootInfo mRoot;
     private String mConfigKey;
 
@@ -49,6 +54,7 @@ final class DirectoryState {
         mPendingOperation = bundle.getParcelable(FileOperationService.EXTRA_OPERATION);
         mLastSortDimensionId = bundle.getInt(EXTRA_SORT_DIMENSION_ID);
         mLastSortDirection = bundle.getInt(EXTRA_SORT_DIRECTION);
+        mSelectionId = bundle.getString(EXTRA_SELECTION_ID);
     }
 
     public void save(Bundle bundle) {
@@ -57,6 +63,7 @@ final class DirectoryState {
         bundle.putParcelable(FileOperationService.EXTRA_OPERATION, mPendingOperation);
         bundle.putInt(EXTRA_SORT_DIMENSION_ID, mLastSortDimensionId);
         bundle.putInt(EXTRA_SORT_DIRECTION, mLastSortDirection);
+        bundle.putString(EXTRA_SELECTION_ID, mSelectionId);
     }
 
     public FileOperation claimPendingOperation() {
@@ -65,11 +72,6 @@ final class DirectoryState {
         return op;
     }
 
-    public void update(RootInfo root, DocumentInfo doc) {
-        mRoot = root;
-        mDocument = doc;
-    }
-
     String getConfigKey() {
         if (mConfigKey == null) {
             final StringBuilder builder = new StringBuilder();
diff --git a/src/com/android/documentsui/dirlist/DocsItemDetailsLookup.java b/src/com/android/documentsui/dirlist/DocsItemDetailsLookup.java
index bc4494cf8..6f16b7632 100644
--- a/src/com/android/documentsui/dirlist/DocsItemDetailsLookup.java
+++ b/src/com/android/documentsui/dirlist/DocsItemDetailsLookup.java
@@ -15,18 +15,19 @@
  */
 package com.android.documentsui.dirlist;
 
+import android.view.MotionEvent;
+import android.view.View;
+
 import androidx.annotation.Nullable;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.RecyclerView.ViewHolder;
-import android.view.MotionEvent;
-import android.view.View;
 
-import com.android.documentsui.selection.ItemDetailsLookup;
+import com.android.documentsui.DocsSelectionHelper.DocDetailsLookup;
 
 /**
  * Access to details of an item associated with a {@link MotionEvent} instance.
  */
-final class DocsItemDetailsLookup extends ItemDetailsLookup {
+final class DocsItemDetailsLookup extends DocDetailsLookup {
 
     private final RecyclerView mRecView;
 
@@ -35,47 +36,7 @@ final class DocsItemDetailsLookup extends ItemDetailsLookup {
     }
 
     @Override
-    public boolean overItem(MotionEvent e) {
-        return getItemPosition(e) != RecyclerView.NO_POSITION;
-    }
-
-    @Override
-    public boolean overStableItem(MotionEvent e) {
-    if (!overItem(e)) {
-        return false;
-    }
-    ItemDetails details = getItemDetails(e);
-    return details != null && details.hasStableId();
-    }
-
-    @Override
-    public boolean inItemDragRegion(MotionEvent e) {
-    if (!overItem(e)) {
-        return false;
-    }
-    ItemDetails details = getItemDetails(e);
-    return details != null && details.inDragRegion(e);
-    }
-
-    @Override
-    public boolean inItemSelectRegion(MotionEvent e) {
-    if (!overItem(e)) {
-        return false;
-    }
-    ItemDetails details = getItemDetails(e);
-    return details != null && details.inSelectionHotspot(e);
-    }
-
-    @Override
-    public int getItemPosition(MotionEvent e) {
-        View child = mRecView.findChildViewUnder(e.getX(), e.getY());
-        return (child != null)
-                ? mRecView.getChildAdapterPosition(child)
-                : RecyclerView.NO_POSITION;
-    }
-
-    @Override
-    public ItemDetails getItemDetails(MotionEvent e) {
+    public DocumentItemDetails getItemDetails(MotionEvent e) {
         @Nullable DocumentHolder holder = getDocumentHolder(e);
         return holder == null ? null : holder.getItemDetails();
     }
diff --git a/src/com/android/documentsui/dirlist/DocsSelectionPredicate.java b/src/com/android/documentsui/dirlist/DocsSelectionPredicate.java
index 5ceb4617a..167cf1dbc 100644
--- a/src/com/android/documentsui/dirlist/DocsSelectionPredicate.java
+++ b/src/com/android/documentsui/dirlist/DocsSelectionPredicate.java
@@ -21,19 +21,20 @@ import static com.android.documentsui.base.DocumentInfo.getCursorString;
 
 import android.database.Cursor;
 import android.provider.DocumentsContract.Document;
+
+import androidx.recyclerview.selection.SelectionTracker.SelectionPredicate;
 import androidx.recyclerview.widget.RecyclerView;
 import android.util.Log;
 
 import com.android.documentsui.ActivityConfig;
 import com.android.documentsui.Model;
 import com.android.documentsui.base.State;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
 
 /**
  * Class embodying the logic as to whether an item (specified by id or position)
  * can be selected (or not).
  */
-final class DocsSelectionPredicate extends SelectionPredicate {
+final class DocsSelectionPredicate extends SelectionPredicate<String> {
 
     private ActivityConfig mConfig;
     private Model mModel;
@@ -56,7 +57,7 @@ final class DocsSelectionPredicate extends SelectionPredicate {
     }
 
     @Override
-    public boolean canSetStateForId(String id, boolean nextState) {
+    public boolean canSetStateForKey(String id, boolean nextState) {
         if (nextState) {
             // Check if an item can be selected
             final Cursor cursor = mModel.getItem(id);
diff --git a/src/com/android/documentsui/dirlist/DocsStableIdProvider.java b/src/com/android/documentsui/dirlist/DocsStableIdProvider.java
index 96390df59..6ff73f279 100644
--- a/src/com/android/documentsui/dirlist/DocsStableIdProvider.java
+++ b/src/com/android/documentsui/dirlist/DocsStableIdProvider.java
@@ -17,9 +17,7 @@ package com.android.documentsui.dirlist;
 
 import static androidx.core.util.Preconditions.checkArgument;
 
-import com.android.documentsui.selection.SelectionHelper.StableIdProvider;
-
-import java.util.List;
+import com.android.documentsui.DocsSelectionHelper.StableIdProvider;
 
 /**
  * Provides RecyclerView selection code access to stable ids backed
@@ -35,7 +33,7 @@ public final class DocsStableIdProvider extends StableIdProvider {
     }
 
     @Override
-    public String getStableId(int position) {
+    public String getKey(int position) {
         return mAdapter.getStableId(position);
     }
 
@@ -43,9 +41,4 @@ public final class DocsStableIdProvider extends StableIdProvider {
     public int getPosition(String id) {
         return mAdapter.getPosition(id);
     }
-
-    @Override
-    public List<String> getStableIds() {
-        return mAdapter.getStableIds();
-    }
 }
diff --git a/src/com/android/documentsui/dirlist/DocumentHolder.java b/src/com/android/documentsui/dirlist/DocumentHolder.java
index 7854dc452..c1c5c1ee3 100644
--- a/src/com/android/documentsui/dirlist/DocumentHolder.java
+++ b/src/com/android/documentsui/dirlist/DocumentHolder.java
@@ -18,7 +18,6 @@ package com.android.documentsui.dirlist;
 
 import android.content.Context;
 import android.database.Cursor;
-import androidx.recyclerview.widget.RecyclerView;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
@@ -27,11 +26,15 @@ import android.view.ViewGroup;
 import android.view.ViewPropertyAnimator;
 import android.widget.ImageView;
 
+import androidx.recyclerview.widget.RecyclerView;
+
 import com.android.documentsui.base.Shared;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 
 import javax.annotation.Nullable;
 
+/**
+ * ViewHolder of a document item within a RecyclerView.
+ */
 public abstract class DocumentHolder
         extends RecyclerView.ViewHolder implements View.OnKeyListener {
 
@@ -42,7 +45,7 @@ public abstract class DocumentHolder
     protected @Nullable String mModelId;
 
     // See #addKeyEventListener for details on the need for this field.
-    private KeyboardEventListener mKeyEventListener;
+    private KeyboardEventListener<DocumentItemDetails> mKeyEventListener;
 
     private final DocumentItemDetails mDetails;
 
@@ -56,7 +59,7 @@ public abstract class DocumentHolder
         itemView.setOnKeyListener(this);
 
         mContext = context;
-        mDetails = new DocumentItemDetails();
+        mDetails = new DocumentItemDetails(this);
     }
 
     /**
@@ -94,10 +97,10 @@ public abstract class DocumentHolder
     @Override
     public boolean onKey(View v, int keyCode, KeyEvent event) {
         assert(mKeyEventListener != null);
-        ItemDetails details = getItemDetails();
+        DocumentItemDetails details = getItemDetails();
         return (details == null)
-            ? false
-            : mKeyEventListener.onKey(getItemDetails(),  keyCode,  event);
+                ? false
+                : mKeyEventListener.onKey(details, keyCode, event);
     }
 
     /**
@@ -108,7 +111,7 @@ public abstract class DocumentHolder
      *
      * <p>Ideally we'd not involve DocumentHolder in propagation of events like this.
      */
-    public void addKeyEventListener(KeyboardEventListener listener) {
+    public void addKeyEventListener(KeyboardEventListener<DocumentItemDetails> listener) {
         assert(mKeyEventListener == null);
         mKeyEventListener = listener;
     }
@@ -121,7 +124,7 @@ public abstract class DocumentHolder
         return false;
     }
 
-    public ItemDetails getItemDetails() {
+    public DocumentItemDetails getItemDetails() {
         return mDetails;
     }
 
@@ -148,32 +151,4 @@ public abstract class DocumentHolder
     static ViewPropertyAnimator fade(ImageView view, float alpha) {
         return view.animate().setDuration(Shared.CHECK_ANIMATION_DURATION).alpha(alpha);
     }
-
-    private final class DocumentItemDetails extends ItemDetails {
-
-        @Override
-        public int getPosition() {
-            return DocumentHolder.this.getAdapterPosition();
-        }
-
-        @Override
-        public String getStableId() {
-            return DocumentHolder.this.getModelId();
-        }
-
-        @Override
-        public int getItemViewType() {
-            return DocumentHolder.this.getItemViewType();
-        }
-
-        @Override
-        public boolean inDragRegion(MotionEvent e) {
-            return DocumentHolder.this.inDragRegion(e);
-        }
-
-        @Override
-        public boolean inSelectionHotspot(MotionEvent e) {
-            return DocumentHolder.this.inSelectRegion(e);
-        }
-    }
 }
diff --git a/src/com/android/documentsui/dirlist/DocumentItemDetails.java b/src/com/android/documentsui/dirlist/DocumentItemDetails.java
new file mode 100644
index 000000000..bf6d7ddd5
--- /dev/null
+++ b/src/com/android/documentsui/dirlist/DocumentItemDetails.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.documentsui.dirlist;
+
+import android.view.MotionEvent;
+
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+
+/**
+ * Provide information of a specific RecyclerView item for selection.
+ */
+public final class DocumentItemDetails extends ItemDetails<String> {
+    private final DocumentHolder mDocumentHolder;
+
+    DocumentItemDetails(DocumentHolder holder) {
+        mDocumentHolder = holder;
+    }
+
+    /**
+     * @return The view type of this ViewHolder.
+     */
+    public int getItemViewType() {
+        return mDocumentHolder.getItemViewType();
+    }
+
+    @Override
+    public int getPosition() {
+        return mDocumentHolder.getAdapterPosition();
+    }
+
+    @Override
+    public String getSelectionKey() {
+        return mDocumentHolder.getModelId();
+    }
+
+    @Override
+    public boolean inDragRegion(MotionEvent e) {
+        return mDocumentHolder.inDragRegion(e);
+    }
+
+    @Override
+    public boolean inSelectionHotspot(MotionEvent e) {
+        return mDocumentHolder.inSelectRegion(e);
+    }
+}
diff --git a/src/com/android/documentsui/dirlist/DragHost.java b/src/com/android/documentsui/dirlist/DragHost.java
index 770097d32..c1f9c8cb0 100644
--- a/src/com/android/documentsui/dirlist/DragHost.java
+++ b/src/com/android/documentsui/dirlist/DragHost.java
@@ -20,9 +20,11 @@ import static com.android.documentsui.base.SharedMinimal.DEBUG;
 
 import android.app.Activity;
 import android.content.ClipData;
+import android.util.Log;
 import android.view.DragEvent;
 import android.view.View;
-import android.util.Log;
+
+import androidx.recyclerview.selection.SelectionTracker;
 
 import com.android.documentsui.AbstractActionHandler;
 import com.android.documentsui.AbstractDragHost;
@@ -32,7 +34,6 @@ import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.DocumentStack;
 import com.android.documentsui.base.Lookup;
 import com.android.documentsui.base.State;
-import com.android.documentsui.selection.SelectionHelper;
 import com.android.documentsui.ui.DialogController;
 
 import java.util.function.Predicate;
@@ -45,7 +46,7 @@ class DragHost<T extends Activity & AbstractActionHandler.CommonAddons> extends
     private static final String TAG = "dirlist.DragHost";
 
     private final T mActivity;
-    private final SelectionHelper mSelectionMgr;
+    private final SelectionTracker<String> mSelectionMgr;
     private final ActionHandler mActions;
     private final State mState;
     private final DialogController mDialogs;
@@ -56,7 +57,7 @@ class DragHost<T extends Activity & AbstractActionHandler.CommonAddons> extends
     DragHost(
             T activity,
             DragAndDropManager dragAndDropManager,
-            SelectionHelper selectionMgr,
+            SelectionTracker<String> selectionMgr,
             ActionHandler actions,
             State state,
             DialogController dialogs,
diff --git a/src/com/android/documentsui/dirlist/DragStartListener.java b/src/com/android/documentsui/dirlist/DragStartListener.java
index e3fa088a6..e88967573 100644
--- a/src/com/android/documentsui/dirlist/DragStartListener.java
+++ b/src/com/android/documentsui/dirlist/DragStartListener.java
@@ -17,24 +17,23 @@
 package com.android.documentsui.dirlist;
 
 import static com.android.documentsui.base.SharedMinimal.DEBUG;
-import static androidx.core.util.Preconditions.checkArgument;
 
 import android.net.Uri;
-import androidx.annotation.VisibleForTesting;
 import android.util.Log;
 import android.view.MotionEvent;
 import android.view.View;
 
+import androidx.annotation.VisibleForTesting;
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.Selection;
+import androidx.recyclerview.selection.SelectionTracker;
+
 import com.android.documentsui.DragAndDropManager;
 import com.android.documentsui.MenuManager.SelectionDetails;
 import com.android.documentsui.Model;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.Events;
 import com.android.documentsui.base.State;
-import com.android.documentsui.selection.ItemDetailsLookup;
-import com.android.documentsui.selection.MutableSelection;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.SelectionHelper;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -51,17 +50,12 @@ interface DragStartListener {
 
     static final DragStartListener DUMMY = new DragStartListener() {
         @Override
-        public boolean onMouseDragEvent(MotionEvent event) {
-            return false;
-        }
-        @Override
-        public boolean onTouchDragEvent(MotionEvent event) {
+        public boolean onDragEvent(MotionEvent event) {
             return false;
         }
     };
 
-    boolean onMouseDragEvent(MotionEvent event);
-    boolean onTouchDragEvent(MotionEvent event);
+    boolean onDragEvent(MotionEvent event);
 
     @VisibleForTesting
     class RuntimeDragStartListener implements DragStartListener {
@@ -70,12 +64,11 @@ interface DragStartListener {
 
         private final IconHelper mIconHelper;
         private final State mState;
-        private final ItemDetailsLookup mDetailsLookup;
-        private final SelectionHelper mSelectionMgr;
+        private final SelectionTracker<String> mSelectionMgr;
         private final SelectionDetails mSelectionDetails;
         private final ViewFinder mViewFinder;
         private final Function<View, String> mIdFinder;
-        private final Function<Selection, List<DocumentInfo>> mDocsConverter;
+        private final Function<Selection<String>, List<DocumentInfo>> mDocsConverter;
         private final DragAndDropManager mDragAndDropManager;
 
 
@@ -84,17 +77,15 @@ interface DragStartListener {
         public RuntimeDragStartListener(
                 IconHelper iconHelper,
                 State state,
-                ItemDetailsLookup detailsLookup,
-                SelectionHelper selectionMgr,
+                SelectionTracker<String> selectionMgr,
                 SelectionDetails selectionDetails,
                 ViewFinder viewFinder,
                 Function<View, String> idFinder,
-                Function<Selection, List<DocumentInfo>> docsConverter,
+                Function<Selection<String>, List<DocumentInfo>> docsConverter,
                 DragAndDropManager dragAndDropManager) {
 
             mIconHelper = iconHelper;
             mState = state;
-            mDetailsLookup = detailsLookup;
             mSelectionMgr = selectionMgr;
             mSelectionDetails = selectionDetails;
             mViewFinder = viewFinder;
@@ -104,15 +95,7 @@ interface DragStartListener {
         }
 
         @Override
-        public final boolean onMouseDragEvent(MotionEvent event) {
-            checkArgument(Events.isMouseDragEvent(event));
-            checkArgument(mDetailsLookup.inItemDragRegion(event));
-
-            return startDrag(mViewFinder.findView(event.getX(), event.getY()), event);
-        }
-
-        @Override
-        public final boolean onTouchDragEvent(MotionEvent event) {
+        public final boolean onDragEvent(MotionEvent event) {
             return startDrag(mViewFinder.findView(event.getX(), event.getY()), event);
         }
 
@@ -132,7 +115,7 @@ interface DragStartListener {
                 return false;
             }
 
-            Selection selection = getSelectionToBeCopied(modelId, event);
+            Selection<String> selection = getSelectionToBeCopied(modelId, event);
 
             final List<DocumentInfo> srcs = mDocsConverter.apply(selection);
 
@@ -158,8 +141,8 @@ interface DragStartListener {
          * coordinates of the event, return a valid selection for drag and drop operation
          */
         @VisibleForTesting
-        MutableSelection getSelectionToBeCopied(String modelId, MotionEvent event) {
-            MutableSelection selection = new MutableSelection();
+        MutableSelection<String> getSelectionToBeCopied(String modelId, MotionEvent event) {
+            MutableSelection<String> selection = new MutableSelection<>();
             // If CTRL-key is held down and there's other existing selection, add item to
             // selection (if not already selected)
             if (Events.isCtrlKeyPressed(event)
@@ -181,10 +164,9 @@ interface DragStartListener {
     static DragStartListener create(
             IconHelper iconHelper,
             Model model,
-            SelectionHelper selectionMgr,
+            SelectionTracker<String> selectionMgr,
             SelectionDetails selectionDetails,
             State state,
-            ItemDetailsLookup detailsLookup,
             Function<View, String> idFinder,
             ViewFinder viewFinder,
             DragAndDropManager dragAndDropManager) {
@@ -192,7 +174,6 @@ interface DragStartListener {
         return new RuntimeDragStartListener(
                 iconHelper,
                 state,
-                detailsLookup,
                 selectionMgr,
                 selectionDetails,
                 viewFinder,
diff --git a/src/com/android/documentsui/dirlist/FocusHandler.java b/src/com/android/documentsui/dirlist/FocusHandler.java
index 03cf23380..2c7f8e672 100644
--- a/src/com/android/documentsui/dirlist/FocusHandler.java
+++ b/src/com/android/documentsui/dirlist/FocusHandler.java
@@ -62,7 +62,7 @@ public interface FocusHandler extends View.OnFocusChangeListener {
     /**
      * @return The adapter position of the last focused item.
      */
-    int getFocusPosition();
+    int getFocusedPosition();
 
     /**
      * @return True if there is currently an item in focus, false otherwise.
diff --git a/src/com/android/documentsui/dirlist/InputHandlers.java b/src/com/android/documentsui/dirlist/InputHandlers.java
index 2943c80a2..8cc2bfb74 100644
--- a/src/com/android/documentsui/dirlist/InputHandlers.java
+++ b/src/com/android/documentsui/dirlist/InputHandlers.java
@@ -17,22 +17,14 @@ package com.android.documentsui.dirlist;
 
 import static androidx.core.util.Preconditions.checkArgument;
 
+import android.view.KeyEvent;
+
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.selection.SelectionTracker.SelectionPredicate;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.RecyclerView.ViewHolder;
-import android.view.HapticFeedbackConstants;
-import android.view.KeyEvent;
-import android.view.MotionEvent;
 
 import com.android.documentsui.ActionHandler;
-import com.android.documentsui.base.EventHandler;
-import com.android.documentsui.base.State;
-import com.android.documentsui.selection.GestureSelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup;
-import com.android.documentsui.selection.MouseInputHandler;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.TouchInputHandler;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
 
 /**
  * Helper class dedicated to building gesture input handlers. The construction
@@ -43,43 +35,36 @@ import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
 final class InputHandlers {
 
     private ActionHandler mActions;
-    private SelectionHelper mSelectionHelper;
-    private SelectionPredicate mSelectionPredicate;
-    private ItemDetailsLookup mDetailsLookup;
+    private SelectionTracker<String> mSelectionHelper;
+    private SelectionPredicate<String> mSelectionPredicate;
     private FocusHandler mFocusHandler;
     private RecyclerView mRecView;
-    private State mState;
 
     InputHandlers(
             ActionHandler actions,
-            SelectionHelper selectionHelper,
-            SelectionPredicate selectionPredicate,
-            ItemDetailsLookup detailsLookup,
+            SelectionTracker<String> selectionHelper,
+            SelectionPredicate<String> selectionPredicate,
             FocusHandler focusHandler,
-            RecyclerView recView,
-            State state) {
+            RecyclerView recView) {
 
         checkArgument(actions != null);
         checkArgument(selectionHelper != null);
         checkArgument(selectionPredicate != null);
-        checkArgument(detailsLookup != null);
         checkArgument(focusHandler != null);
         checkArgument(recView != null);
-        checkArgument(state != null);
 
         mActions = actions;
         mSelectionHelper = selectionHelper;
         mSelectionPredicate = selectionPredicate;
-        mDetailsLookup = detailsLookup;
         mFocusHandler = focusHandler;
         mRecView = recView;
-        mState = state;
     }
 
     KeyInputHandler createKeyHandler() {
-        KeyInputHandler.Callbacks callbacks = new KeyInputHandler.Callbacks() {
+        KeyInputHandler.Callbacks<DocumentItemDetails> callbacks =
+                new KeyInputHandler.Callbacks<DocumentItemDetails>() {
             @Override
-            public boolean isInteractiveItem(ItemDetails item, KeyEvent e) {
+            public boolean isInteractiveItem(DocumentItemDetails item, KeyEvent e) {
                 switch (item.getItemViewType()) {
                     case DocumentsAdapter.ITEM_TYPE_HEADER_MESSAGE:
                     case DocumentsAdapter.ITEM_TYPE_INFLATED_MESSAGE:
@@ -95,7 +80,7 @@ final class InputHandlers {
             }
 
             @Override
-            public boolean onItemActivated(ItemDetails item, KeyEvent e) {
+            public boolean onItemActivated(DocumentItemDetails item, KeyEvent e) {
                 // Handle enter key events
                 switch (e.getKeyCode()) {
                     case KeyEvent.KEYCODE_ENTER:
@@ -116,7 +101,7 @@ final class InputHandlers {
             }
 
             @Override
-            public boolean onFocusItem(ItemDetails details, int keyCode, KeyEvent event) {
+            public boolean onFocusItem(DocumentItemDetails details, int keyCode, KeyEvent event) {
                 ViewHolder holder =
                         mRecView.findViewHolderForAdapterPosition(details.getPosition());
                 if (holder instanceof DocumentHolder) {
@@ -124,104 +109,8 @@ final class InputHandlers {
                 }
                 return false;
             }
-
-            @Override
-            public void onPerformHapticFeedback() {
-                mRecView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
-            }
         };
 
         return new KeyInputHandler(mSelectionHelper, mSelectionPredicate, callbacks);
     }
-
-    MouseInputHandler createMouseHandler(
-            EventHandler<MotionEvent> showContextMenuCallback) {
-
-        checkArgument(showContextMenuCallback != null);
-
-        MouseInputHandler.Callbacks callbacks = new MouseInputHandler.Callbacks() {
-            @Override
-            public boolean onItemActivated(ItemDetails item, MotionEvent e) {
-                return mActions.openItem(
-                        item,
-                        ActionHandler.VIEW_TYPE_REGULAR,
-                        ActionHandler.VIEW_TYPE_PREVIEW);
-            }
-
-            @Override
-            public boolean onContextClick(MotionEvent e) {
-                return showContextMenuCallback.accept(e);
-            }
-
-            @Override
-            public void onPerformHapticFeedback() {
-                mRecView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
-            }
-
-            @Override
-            public void focusItem(ItemDetails item) {
-                mFocusHandler.focusDocument(item.getStableId());
-            }
-
-            @Override
-            public void clearFocus() {
-                mFocusHandler.clearFocus();
-            }
-
-            @Override
-            public boolean hasFocusedItem() {
-                return mFocusHandler.hasFocusedItem();
-            }
-
-            @Override
-            public int getFocusedPosition() {
-                return mFocusHandler.getFocusPosition();
-            }
-        };
-
-        return new MouseInputHandler(mSelectionHelper, mDetailsLookup, callbacks);
-    }
-
-    /**
-     * Factory method for input touch delegate. Exists to reduce complexity in the
-     * calling scope.
-     * @param gestureHelper
-     */
-    TouchInputHandler createTouchHandler(
-            GestureSelectionHelper gestureHelper, DragStartListener dragStartListener) {
-        checkArgument(dragStartListener != null);
-
-        TouchInputHandler.Callbacks callbacks = new TouchInputHandler.Callbacks() {
-            @Override
-            public boolean onItemActivated(ItemDetails item, MotionEvent e) {
-                return mActions.openItem(
-                        item,
-                        ActionHandler.VIEW_TYPE_PREVIEW,
-                        ActionHandler.VIEW_TYPE_REGULAR);
-            }
-
-            @Override
-            public boolean onDragInitiated(MotionEvent e) {
-                return dragStartListener.onTouchDragEvent(e);
-            }
-
-            @Override
-            public void onPerformHapticFeedback() {
-                mRecView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
-            }
-
-            @Override
-            public void focusItem(ItemDetails item) {
-                mFocusHandler.focusDocument(item.getStableId());
-            }
-
-            @Override
-            public void clearFocus() {
-                mFocusHandler.clearFocus();
-            }
-        };
-
-        return new TouchInputHandler(
-                mSelectionHelper, mDetailsLookup, mSelectionPredicate, gestureHelper, callbacks);
-    }
 }
diff --git a/src/com/android/documentsui/dirlist/KeyInputHandler.java b/src/com/android/documentsui/dirlist/KeyInputHandler.java
index 6e82c3e0e..826270ea1 100644
--- a/src/com/android/documentsui/dirlist/KeyInputHandler.java
+++ b/src/com/android/documentsui/dirlist/KeyInputHandler.java
@@ -17,31 +17,30 @@ package com.android.documentsui.dirlist;
 
 import android.view.KeyEvent;
 
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+import androidx.recyclerview.selection.SelectionTracker.SelectionPredicate;
+
 import com.android.documentsui.base.Events;
-import com.android.documentsui.selection.ItemDetailsLookup;
-import com.android.documentsui.selection.MotionInputHandler;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-import com.android.documentsui.selection.MotionInputHandler.Callbacks;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
 
 import javax.annotation.Nullable;
 
+// TODO(b/69058726): Migrate to RecyclerView-Selection
 /**
  * Class that handles keyboard events on RecyclerView items. The input handler
  * must be attached directly to a RecyclerView item since, unlike DOM, events
  * don't appear bubble up.
  */
-public final class KeyInputHandler extends KeyboardEventListener {
+public final class KeyInputHandler extends KeyboardEventListener<DocumentItemDetails> {
 
-    private final SelectionHelper mSelectionHelper;
-    private final SelectionPredicate mSelectionPredicate;
-    private final Callbacks mCallbacks;
+    private final SelectionTracker<String> mSelectionHelper;
+    private final SelectionPredicate<String> mSelectionPredicate;
+    private final Callbacks<DocumentItemDetails> mCallbacks;
 
     public KeyInputHandler(
-            SelectionHelper selectionHelper,
-            SelectionPredicate selectionPredicate,
-            Callbacks callbacks) {
+            SelectionTracker<String> selectionHelper,
+            SelectionPredicate<String> selectionPredicate,
+            Callbacks<DocumentItemDetails> callbacks) {
 
         mSelectionHelper = selectionHelper;
         mSelectionPredicate = selectionPredicate;
@@ -49,7 +48,7 @@ public final class KeyInputHandler extends KeyboardEventListener {
     }
 
     @Override
-    public boolean onKey(@Nullable ItemDetails details, int keyCode, KeyEvent event) {
+    public boolean onKey(@Nullable DocumentItemDetails details, int keyCode, KeyEvent event) {
         // Only handle key-down events. This is simpler, consistent with most other UIs, and
         // enables the handling of repeated key events from holding down a key.
         if (event.getAction() != KeyEvent.ACTION_DOWN) {
@@ -96,17 +95,17 @@ public final class KeyInputHandler extends KeyboardEventListener {
         return mCallbacks.onItemActivated(details, event);
     }
 
-    private boolean shouldExtendSelection(ItemDetails item, KeyEvent event) {
+    private boolean shouldExtendSelection(DocumentItemDetails item, KeyEvent event) {
         if (!Events.isNavigationKeyCode(event.getKeyCode()) || !event.isShiftPressed()) {
             return false;
         }
 
-        return mSelectionPredicate.canSetStateForId(item.getStableId(), true);
+        return mSelectionPredicate.canSetStateForKey(item.getSelectionKey(), true);
     }
 
-    public static abstract class Callbacks extends MotionInputHandler.Callbacks {
-        public abstract boolean isInteractiveItem(ItemDetails item, KeyEvent e);
-        public abstract boolean onItemActivated(ItemDetails item, KeyEvent e);
-        public abstract boolean onFocusItem(ItemDetails details, int keyCode, KeyEvent event);
+    public static abstract class Callbacks<T extends ItemDetails<?>> {
+        public abstract boolean isInteractiveItem(T item, KeyEvent e);
+        public abstract boolean onItemActivated(T item, KeyEvent e);
+        public abstract boolean onFocusItem(T details, int keyCode, KeyEvent event);
     }
 }
diff --git a/src/com/android/documentsui/dirlist/KeyboardEventListener.java b/src/com/android/documentsui/dirlist/KeyboardEventListener.java
index fb1fc0a6b..d45885de6 100644
--- a/src/com/android/documentsui/dirlist/KeyboardEventListener.java
+++ b/src/com/android/documentsui/dirlist/KeyboardEventListener.java
@@ -17,14 +17,13 @@ package com.android.documentsui.dirlist;
 
 import android.view.KeyEvent;
 
-import com.android.documentsui.selection.ItemDetailsLookup;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
 
 /**
  * KeyboardListener is implemented by {@link KeyInputHandler}. The handler
  * must be called from RecyclerView.Holders in response to keyboard events.
  */
-public abstract class KeyboardEventListener {
+public abstract class KeyboardEventListener<T extends ItemDetails<?>> {
 
     /**
      * Handles key events on the view holder.
@@ -35,5 +34,5 @@ public abstract class KeyboardEventListener {
      *
      * @return Whether the event was handled.
      */
-    public abstract boolean onKey(ItemDetails details, int keyCode, KeyEvent event);
+    public abstract boolean onKey(T details, int keyCode, KeyEvent event);
 }
diff --git a/src/com/android/documentsui/dirlist/MessageHolder.java b/src/com/android/documentsui/dirlist/MessageHolder.java
index 92686025b..1d8d7d61c 100644
--- a/src/com/android/documentsui/dirlist/MessageHolder.java
+++ b/src/com/android/documentsui/dirlist/MessageHolder.java
@@ -16,10 +16,7 @@
 
 package com.android.documentsui.dirlist;
 
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-
 import android.content.Context;
-import android.view.MotionEvent;
 import android.view.ViewGroup;
 import android.widget.Space;
 
@@ -36,7 +33,7 @@ abstract class MessageHolder extends DocumentHolder {
     }
 
     @Override
-    public ItemDetails getItemDetails() {
+    public DocumentItemDetails getItemDetails() {
         return null;
     }
 }
diff --git a/src/com/android/documentsui/dirlist/ModelBackedDocumentsAdapter.java b/src/com/android/documentsui/dirlist/ModelBackedDocumentsAdapter.java
index 85be6a692..604badf4f 100644
--- a/src/com/android/documentsui/dirlist/ModelBackedDocumentsAdapter.java
+++ b/src/com/android/documentsui/dirlist/ModelBackedDocumentsAdapter.java
@@ -23,16 +23,17 @@ import static com.android.documentsui.base.State.MODE_LIST;
 
 import android.database.Cursor;
 import android.provider.DocumentsContract.Document;
-import androidx.recyclerview.widget.RecyclerView;
 import android.util.Log;
 import android.view.ViewGroup;
 
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.widget.RecyclerView;
+
 import com.android.documentsui.Model;
 import com.android.documentsui.Model.Update;
 import com.android.documentsui.base.EventListener;
 import com.android.documentsui.base.Lookup;
 import com.android.documentsui.base.State;
-import com.android.documentsui.selection.SelectionHelper;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -111,7 +112,7 @@ final class ModelBackedDocumentsAdapter extends DocumentsAdapter {
 
     @Override
     public void onBindViewHolder(DocumentHolder holder, int position, List<Object> payload) {
-        if (payload.contains(SelectionHelper.SELECTION_CHANGED_MARKER)) {
+        if (payload.contains(SelectionTracker.SELECTION_CHANGED_MARKER)) {
             final boolean selected = mEnv.isSelected(mModelIds.get(position));
             holder.setSelected(selected, true);
         } else {
diff --git a/src/com/android/documentsui/dirlist/MouseDragEventInterceptor.java b/src/com/android/documentsui/dirlist/MouseDragEventInterceptor.java
deleted file mode 100644
index 2aba9277c..000000000
--- a/src/com/android/documentsui/dirlist/MouseDragEventInterceptor.java
+++ /dev/null
@@ -1,80 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.dirlist;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import androidx.annotation.Nullable;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener;
-import android.view.MotionEvent;
-
-import com.android.documentsui.base.EventHandler;
-import com.android.documentsui.base.Events;
-import com.android.documentsui.selection.BandSelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup;
-import com.android.documentsui.selection.TouchEventRouter;
-
-/**
- * OnItemTouchListener that helps enable support for drag/drop functionality
- * in DirectoryFragment.
- *
- * <p>This class takes an OnItemTouchListener that is presumably the
- * one provided by {@link BandSelectionHelper#getListener()}, and
- * is used in conjunction with the {@link TouchEventRouter}.
- *
- * <p>See DirectoryFragment for more details on how this is glued
- * into DocumetnsUI event handling to make the magic happen.
- */
-class MouseDragEventInterceptor implements OnItemTouchListener {
-
-    private final ItemDetailsLookup mEventDetailsLookup;
-    private final EventHandler<MotionEvent> mMouseDragListener;
-    private final @Nullable OnItemTouchListener mDelegate;
-
-    public MouseDragEventInterceptor(
-            ItemDetailsLookup eventDetailsLookup,
-            EventHandler<MotionEvent> mouseDragListener,
-            @Nullable OnItemTouchListener delegate) {
-
-        checkArgument(eventDetailsLookup != null);
-        checkArgument(mouseDragListener != null);
-
-        mEventDetailsLookup = eventDetailsLookup;
-        mMouseDragListener = mouseDragListener;
-        mDelegate = delegate;
-    }
-
-    @Override
-    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
-        if (Events.isMouseDragEvent(e) && mEventDetailsLookup.inItemDragRegion(e)) {
-            return mMouseDragListener.accept(e);
-        } else if (mDelegate != null) {
-            return mDelegate.onInterceptTouchEvent(rv, e);
-        }
-        return false;
-    }
-
-    @Override
-    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
-        if (mDelegate != null) {
-            mDelegate.onTouchEvent(rv, e);
-        }
-    }
-
-    @Override
-    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {}
-}
diff --git a/src/com/android/documentsui/dirlist/SelectionMetadata.java b/src/com/android/documentsui/dirlist/SelectionMetadata.java
index 3ac3a0741..3abc3e190 100644
--- a/src/com/android/documentsui/dirlist/SelectionMetadata.java
+++ b/src/com/android/documentsui/dirlist/SelectionMetadata.java
@@ -23,11 +23,12 @@ import android.database.Cursor;
 import android.provider.DocumentsContract.Document;
 import android.util.Log;
 
+import androidx.recyclerview.selection.SelectionTracker.SelectionObserver;
+
 import com.android.documentsui.MenuManager;
 import com.android.documentsui.archives.ArchivesProvider;
 import com.android.documentsui.base.MimeTypes;
 import com.android.documentsui.roots.RootCursorWrapper;
-import com.android.documentsui.selection.SelectionHelper.SelectionObserver;
 
 import java.util.function.Function;
 
@@ -38,7 +39,7 @@ import java.util.function.Function;
  * <p>By collecting information in real-time as the selection changes the need to
  * traverse the entire selection in order to answer questions is eliminated.
  */
-public class SelectionMetadata extends SelectionObserver
+public class SelectionMetadata extends SelectionObserver<String>
         implements MenuManager.SelectionDetails {
 
     private static final String TAG = "SelectionMetadata";
@@ -107,7 +108,7 @@ public class SelectionMetadata extends SelectionObserver
     }
 
     @Override
-    public void onSelectionReset() {
+    public void onSelectionRefresh() {
         mFileCount = 0;
         mDirectoryCount = 0;
         mPartialCount = 0;
diff --git a/src/com/android/documentsui/files/ActionHandler.java b/src/com/android/documentsui/files/ActionHandler.java
index 19c812ffd..62ae87807 100644
--- a/src/com/android/documentsui/files/ActionHandler.java
+++ b/src/com/android/documentsui/files/ActionHandler.java
@@ -31,6 +31,10 @@ import android.util.Log;
 import android.view.DragEvent;
 import android.view.View;
 
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.Selection;
+
 import com.android.documentsui.AbstractActionHandler;
 import com.android.documentsui.ActionModeAddons;
 import com.android.documentsui.ActivityConfig;
@@ -60,9 +64,6 @@ import com.android.documentsui.files.ActionHandler.Addons;
 import com.android.documentsui.inspector.InspectorActivity;
 import com.android.documentsui.queries.SearchViewManager;
 import com.android.documentsui.roots.ProvidersAccess;
-import com.android.documentsui.selection.MutableSelection;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 import com.android.documentsui.services.FileOperation;
 import com.android.documentsui.services.FileOperationService;
 import com.android.documentsui.services.FileOperations;
@@ -140,7 +141,7 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
 
     @Override
     public void openSelectedInNewWindow() {
-        Selection selection = getStableSelection();
+        Selection<String> selection = getStableSelection();
         assert(selection.size() == 1);
         DocumentInfo doc = mModel.getDocument(selection.iterator().next());
         assert(doc != null);
@@ -194,12 +195,12 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     }
 
     @Override
-    public boolean openItem(ItemDetails details, @ViewType int type,
+    public boolean openItem(ItemDetails<String> details, @ViewType int type,
             @ViewType int fallback) {
-        DocumentInfo doc = mModel.getDocument(details.getStableId());
+        DocumentInfo doc = mModel.getDocument(details.getSelectionKey());
         if (doc == null) {
-            Log.w(TAG,
-                    "Can't view item. No Document available for modeId: " + details.getStableId());
+            Log.w(TAG, "Can't view item. No Document available for modeId: "
+                    + details.getSelectionKey());
             return false;
         }
 
@@ -224,8 +225,8 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
         openContainerDocument(doc);
     }
 
-    private Selection getSelectedOrFocused() {
-        final MutableSelection selection = this.getStableSelection();
+    private Selection<String> getSelectedOrFocused() {
+        final MutableSelection<String> selection = this.getStableSelection();
         if (selection.isEmpty()) {
             String focusModelId = mFocusHandler.getFocusModelId();
             if (focusModelId != null) {
@@ -239,7 +240,7 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     @Override
     public void cutToClipboard() {
         Metrics.logUserAction(mActivity, Metrics.USER_ACTION_CUT_CLIPBOARD);
-        Selection selection = getSelectedOrFocused();
+        Selection<String> selection = getSelectedOrFocused();
 
         if (selection.isEmpty()) {
             return;
@@ -260,7 +261,7 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     @Override
     public void copyToClipboard() {
         Metrics.logUserAction(mActivity, Metrics.USER_ACTION_COPY_CLIPBOARD);
-        Selection selection = getSelectedOrFocused();
+        Selection<String> selection = getSelectedOrFocused();
 
         if (selection.isEmpty()) {
             return;
@@ -275,7 +276,7 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     @Override
     public void viewInOwner() {
         Metrics.logUserAction(mActivity, Metrics.USER_ACTION_VIEW_IN_APPLICATION);
-        Selection selection = getSelectedOrFocused();
+        Selection<String> selection = getSelectedOrFocused();
 
         if (selection.isEmpty() || selection.size() > 1) {
             return;
@@ -297,7 +298,7 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     @Override
     public void deleteSelectedDocuments() {
         Metrics.logUserAction(mActivity, Metrics.USER_ACTION_DELETE);
-        Selection selection = getSelectedOrFocused();
+        Selection<String> selection = getSelectedOrFocused();
 
         if (selection.isEmpty()) {
             return;
@@ -362,7 +363,7 @@ public class ActionHandler<T extends Activity & Addons> extends AbstractActionHa
     public void shareSelectedDocuments() {
         Metrics.logUserAction(mActivity, Metrics.USER_ACTION_SHARE);
 
-        Selection selection = getStableSelection();
+        Selection<String> selection = getStableSelection();
 
         assert(!selection.isEmpty());
 
diff --git a/src/com/android/documentsui/files/FilesActivity.java b/src/com/android/documentsui/files/FilesActivity.java
index e8cdc642f..c07deb6ed 100644
--- a/src/com/android/documentsui/files/FilesActivity.java
+++ b/src/com/android/documentsui/files/FilesActivity.java
@@ -98,7 +98,7 @@ public class FilesActivity extends BaseActivity implements ActionHandler.Addons
         super.onCreate(icicle);
 
         DocumentClipper clipper = DocumentsApplication.getDocumentClipper(this);
-        mInjector.selectionMgr = DocsSelectionHelper.createMultiSelect();
+        mInjector.selectionMgr = DocsSelectionHelper.create();
 
         mInjector.focusManager = new FocusManager(
                 mInjector.features,
diff --git a/src/com/android/documentsui/files/MenuManager.java b/src/com/android/documentsui/files/MenuManager.java
index bc21a2d49..9bb102c83 100644
--- a/src/com/android/documentsui/files/MenuManager.java
+++ b/src/com/android/documentsui/files/MenuManager.java
@@ -28,15 +28,15 @@ import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 
+import androidx.recyclerview.selection.SelectionTracker;
+
 import com.android.documentsui.R;
-import com.android.documentsui.MenuManager.SelectionDetails;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.Features;
 import com.android.documentsui.base.Lookup;
 import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.base.State;
 import com.android.documentsui.queries.SearchViewManager;
-import com.android.documentsui.selection.SelectionHelper;
 
 import java.util.List;
 import java.util.function.IntFunction;
@@ -45,7 +45,7 @@ public final class MenuManager extends com.android.documentsui.MenuManager {
 
     private final Features mFeatures;
     private final Context mContext;
-    private final SelectionHelper mSelectionManager;
+    private final SelectionTracker<String> mSelectionManager;
     private final Lookup<String, Uri> mUriLookup;
     private final Lookup<String, String> mAppNameLookup;
 
@@ -55,7 +55,7 @@ public final class MenuManager extends com.android.documentsui.MenuManager {
             State displayState,
             DirectoryDetails dirDetails,
             Context context,
-            SelectionHelper selectionManager,
+            SelectionTracker<String> selectionManager,
             Lookup<String, String> appNameLookup,
             Lookup<String, Uri> uriLookup) {
 
diff --git a/src/com/android/documentsui/picker/ActionHandler.java b/src/com/android/documentsui/picker/ActionHandler.java
index f18a7fe6f..ff8a2dd71 100644
--- a/src/com/android/documentsui/picker/ActionHandler.java
+++ b/src/com/android/documentsui/picker/ActionHandler.java
@@ -36,6 +36,8 @@ import android.provider.DocumentsContract;
 import android.provider.Settings;
 import android.util.Log;
 
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+
 import com.android.documentsui.AbstractActionHandler;
 import com.android.documentsui.ActivityConfig;
 import com.android.documentsui.DocumentsAccess;
@@ -54,7 +56,6 @@ import com.android.documentsui.dirlist.AnimationView;
 import com.android.documentsui.picker.ActionHandler.Addons;
 import com.android.documentsui.queries.SearchViewManager;
 import com.android.documentsui.roots.ProvidersAccess;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 import com.android.documentsui.services.FileOperationService;
 import androidx.annotation.VisibleForTesting;
 
@@ -246,12 +247,12 @@ class ActionHandler<T extends Activity & Addons> extends AbstractActionHandler<T
     }
 
     @Override
-    public boolean openItem(ItemDetails details, @ViewType int type,
+    public boolean openItem(ItemDetails<String> details, @ViewType int type,
             @ViewType int fallback) {
-        DocumentInfo doc = mModel.getDocument(details.getStableId());
+        DocumentInfo doc = mModel.getDocument(details.getSelectionKey());
         if (doc == null) {
-            Log.w(TAG,
-                    "Can't view item. No Document available for modeId: " + details.getStableId());
+            Log.w(TAG, "Can't view item. No Document available for modeId: "
+                    + details.getSelectionKey());
             return false;
         }
 
diff --git a/src/com/android/documentsui/picker/PickActivity.java b/src/com/android/documentsui/picker/PickActivity.java
index dc9690e1b..4e1556275 100644
--- a/src/com/android/documentsui/picker/PickActivity.java
+++ b/src/com/android/documentsui/picker/PickActivity.java
@@ -94,9 +94,7 @@ public class PickActivity extends BaseActivity implements ActionHandler.Addons {
 
         super.onCreate(icicle);
 
-        mInjector.selectionMgr = mState.allowMultiple
-                ? DocsSelectionHelper.createMultiSelect()
-                : DocsSelectionHelper.createSingleSelect();
+        mInjector.selectionMgr = DocsSelectionHelper.create();
 
         mInjector.focusManager = new FocusManager(
                 mInjector.features,
diff --git a/src/com/android/documentsui/selection/BandPredicate.java b/src/com/android/documentsui/selection/BandPredicate.java
deleted file mode 100644
index 08d64a81b..000000000
--- a/src/com/android/documentsui/selection/BandPredicate.java
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.MotionEvent;
-import android.view.View;
-
-/**
- * Provides a means of controlling when and where band selection is initiated.
- * This can be used to permit band initiation in non-empty areas, like in the whitespace of
- * a bound view. This is especially useful when there is no empty space between items.
- */
-public abstract class BandPredicate {
-
-    /** @return true if band selection can be initiated in response to the {@link MotionEvent}. */
-    public abstract boolean canInitiate(MotionEvent e);
-
-    /**
-     * A BandPredicate that allows initiation of band selection only in areas of RecyclerView
-     * that have {@link RecyclerView#NO_POSITION}. In most cases, this will be the empty areas
-     * between views.
-     */
-    public static final class NoPositionBandPredicate extends BandPredicate {
-
-        private final RecyclerView mRecView;
-
-        public NoPositionBandPredicate(RecyclerView recView) {
-            checkArgument(recView != null);
-
-            mRecView = recView;
-        }
-
-        @Override
-        public boolean canInitiate(MotionEvent e) {
-            View itemView = mRecView.findChildViewUnder(e.getX(), e.getY());
-            int position = itemView != null
-                    ? mRecView.getChildAdapterPosition(itemView)
-                    : RecyclerView.NO_POSITION;
-
-            return position == RecyclerView.NO_POSITION;
-        }
-    };
-}
diff --git a/src/com/android/documentsui/selection/BandSelectionHelper.java b/src/com/android/documentsui/selection/BandSelectionHelper.java
deleted file mode 100644
index f5aa4665d..000000000
--- a/src/com/android/documentsui/selection/BandSelectionHelper.java
+++ /dev/null
@@ -1,401 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-import static androidx.core.util.Preconditions.checkState;
-import static com.android.documentsui.base.SharedMinimal.DEBUG;
-
-import android.graphics.Point;
-import android.graphics.Rect;
-import android.os.Build;
-import androidx.annotation.Nullable;
-import androidx.annotation.VisibleForTesting;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener;
-import androidx.recyclerview.widget.RecyclerView.OnScrollListener;
-import android.util.Log;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-import com.android.documentsui.selection.SelectionHelper.StableIdProvider;
-import com.android.documentsui.selection.ViewAutoScroller.ScrollHost;
-import com.android.documentsui.selection.ViewAutoScroller.ScrollerCallbacks;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Set;
-
-/**
- * Provides mouse driven band-selection support when used in conjunction with a {@link RecyclerView}
- * instance. This class is responsible for rendering a band overlay and manipulating selection
- * status of the items it intersects with.
- *
- * <p> Given the recycling nature of RecyclerView items that have scrolled off-screen would not
- * be selectable with a band that itself was partially rendered off-screen. To address this,
- * BandSelectionController builds a model of the list/grid information presented by RecyclerView as
- * the user interacts with items using their pointer (and the band). Selectable items that intersect
- * with the band, both on and off screen, are selected on pointer up.
- */
-public class BandSelectionHelper implements OnItemTouchListener {
-
-    static final String TAG = "BandController";
-
-    private final BandHost mHost;
-    private final StableIdProvider mStableIds;
-    private final RecyclerView.Adapter<?> mAdapter;
-    private final SelectionHelper mSelectionHelper;
-    private final SelectionPredicate mSelectionPredicate;
-    private final BandPredicate mBandPredicate;
-    private final ContentLock mLock;
-    private final Runnable mViewScroller;
-    private final GridModel.SelectionObserver mGridObserver;
-    private final List<Runnable> mBandStartedListeners = new ArrayList<>();
-
-    @Nullable private Rect mBounds;
-    @Nullable private Point mCurrentPosition;
-    @Nullable private Point mOrigin;
-    @Nullable private GridModel mModel;
-
-    public BandSelectionHelper(
-            BandHost host,
-            RecyclerView.Adapter<?> adapter,
-            StableIdProvider stableIds,
-            SelectionHelper selectionHelper,
-            SelectionPredicate selectionPredicate,
-            BandPredicate bandPredicate,
-            ContentLock lock) {
-
-        checkArgument(host != null);
-        checkArgument(adapter != null);
-        checkArgument(stableIds != null);
-        checkArgument(selectionHelper != null);
-        checkArgument(selectionPredicate != null);
-        checkArgument(bandPredicate != null);
-        checkArgument(lock != null);
-
-        mHost = host;
-        mStableIds = stableIds;
-        mAdapter = adapter;
-        mSelectionHelper = selectionHelper;
-        mSelectionPredicate = selectionPredicate;
-        mBandPredicate = bandPredicate;
-        mLock = lock;
-
-        mHost.addOnScrollListener(
-                new OnScrollListener() {
-                    @Override
-                    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
-                        BandSelectionHelper.this.onScrolled(recyclerView, dx, dy);
-                    }
-                });
-
-        mViewScroller = new ViewAutoScroller(
-                new ScrollHost() {
-                    @Override
-                    public Point getCurrentPosition() {
-                        return mCurrentPosition;
-                    }
-
-                    @Override
-                    public int getViewHeight() {
-                        return mHost.getHeight();
-                    }
-
-                    @Override
-                    public boolean isActive() {
-                        return BandSelectionHelper.this.isActive();
-                    }
-                },
-                host);
-
-        mAdapter.registerAdapterDataObserver(
-                new RecyclerView.AdapterDataObserver() {
-                    @Override
-                    public void onChanged() {
-                        if (isActive()) {
-                            endBandSelect();
-                        }
-                    }
-
-                    @Override
-                    public void onItemRangeChanged(
-                            int startPosition, int itemCount, Object payload) {
-                        // No change in position. Ignoring.
-                    }
-
-                    @Override
-                    public void onItemRangeInserted(int startPosition, int itemCount) {
-                        if (isActive()) {
-                            endBandSelect();
-                        }
-                    }
-
-                    @Override
-                    public void onItemRangeRemoved(int startPosition, int itemCount) {
-                        assert(startPosition >= 0);
-                        assert(itemCount > 0);
-
-                        // TODO: Should update grid model.
-                    }
-
-                    @Override
-                    public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
-                        throw new UnsupportedOperationException();
-                    }
-                });
-
-        mGridObserver = new GridModel.SelectionObserver() {
-                @Override
-                public void onSelectionChanged(Set<String> updatedSelection) {
-                    mSelectionHelper.setProvisionalSelection(updatedSelection);
-                }
-            };
-    }
-
-    @VisibleForTesting
-    boolean isActive() {
-        boolean active = mModel != null;
-        if (DEBUG && active) {
-            mLock.checkLocked();
-        }
-        return active;
-    }
-
-    /**
-     * Adds a new listener to be notified when band is created.
-     */
-    public void addOnBandStartedListener(Runnable listener) {
-        checkArgument(listener != null);
-
-        mBandStartedListeners.add(listener);
-    }
-
-    /**
-     * Removes listener. No-op if listener was not previously installed.
-     */
-    public void removeOnBandStartedListener(Runnable listener) {
-        mBandStartedListeners.remove(listener);
-    }
-
-    /**
-     * Clients must call reset when there are any material changes to the layout of items
-     * in RecyclerView.
-     */
-    public void reset() {
-        if (!isActive()) {
-            return;
-        }
-
-        mHost.hideBand();
-        mModel.stopCapturing();
-        mModel.onDestroy();
-        mModel = null;
-        mOrigin = null;
-        mLock.unblock();
-    }
-
-    boolean shouldStart(MotionEvent e) {
-        // Don't start, or extend bands on non-left clicks.
-        if (!MotionEvents.isPrimaryButtonPressed(e)) {
-            return false;
-        }
-
-        // TODO: Refactor to NOT have side-effects on this "should" method.
-        // Weird things happen if we keep up band select
-        // when touch events happen.
-        if (isActive() && !MotionEvents.isMouseEvent(e)) {
-            endBandSelect();
-            return false;
-        }
-
-        // b/30146357 && b/23793622. onInterceptTouchEvent does not dispatch events to onTouchEvent
-        // unless the event is != ACTION_DOWN. Thus, we need to actually start band selection when
-        // mouse moves, or else starting band selection on mouse down can cause problems as events
-        // don't get routed correctly to onTouchEvent.
-        return !isActive()
-                && MotionEvents.isActionMove(e)
-                // the initial button move via mouse-touch (ie. down press)
-                // The adapter inserts items for UI layout purposes that aren't
-                // associated with files. Checking against actual modelIds count
-                // effectively ignores those UI layout items.
-                && !mStableIds.getStableIds().isEmpty()
-                && mBandPredicate.canInitiate(e);
-    }
-
-    public boolean shouldStop(MotionEvent e) {
-        return isActive()
-                && MotionEvents.isMouseEvent(e)
-                && (MotionEvents.isActionUp(e)
-                        || MotionEvents.isActionPointerUp(e)
-                        || MotionEvents.isActionCancel(e));
-    }
-
-    @Override
-    public boolean onInterceptTouchEvent(RecyclerView unused, MotionEvent e) {
-        if (shouldStart(e)) {
-            if (!MotionEvents.isCtrlKeyPressed(e)) {
-                mSelectionHelper.clearSelection();
-            }
-
-            startBandSelect(MotionEvents.getOrigin(e));
-            return isActive();
-        }
-
-        if (shouldStop(e)) {
-            endBandSelect();
-            checkState(mModel == null);
-            // fall through to return false, because the band eeess done!
-        }
-
-        return false;
-    }
-
-    /**
-     * Processes a MotionEvent by starting, ending, or resizing the band select overlay.
-     * @param input
-     */
-    @Override
-    public void onTouchEvent(RecyclerView unused, MotionEvent e) {
-        if (shouldStop(e)) {
-            endBandSelect();
-            return;
-        }
-
-        // We shouldn't get any events in this method when band select is not active,
-        // but it turns some guests show up late to the party.
-        // Probably happening when a re-layout is happening to the ReyclerView (ie. Pull-To-Refresh)
-        if (!isActive()) {
-            return;
-        }
-
-        assert MotionEvents.isActionMove(e);
-
-        mCurrentPosition = MotionEvents.getOrigin(e);
-        mModel.resizeSelection(mCurrentPosition);
-
-        scrollViewIfNecessary();
-        resizeBand();
-    }
-
-    @Override
-    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {}
-
-    /**
-     * Starts band select by adding the drawable to the RecyclerView's overlay.
-     */
-    private void startBandSelect(Point origin) {
-        if (DEBUG) Log.d(TAG, "Starting band select @ " + origin);
-
-        reset();
-        mModel = new GridModel(mHost, mStableIds, mSelectionPredicate);
-        mModel.addOnSelectionChangedListener(mGridObserver);
-
-        mLock.block();
-        notifyBandStarted();
-        mOrigin = origin;
-        mModel.startCapturing(mOrigin);
-    }
-
-    private void notifyBandStarted() {
-        for (Runnable listener : mBandStartedListeners) {
-            listener.run();
-        }
-    }
-
-    private void scrollViewIfNecessary() {
-        mHost.removeCallback(mViewScroller);
-        mViewScroller.run();
-        mHost.invalidateView();
-    }
-
-    /**
-     * Resizes the band select rectangle by using the origin and the current pointer position as
-     * two opposite corners of the selection.
-     */
-    private void resizeBand() {
-        mBounds = new Rect(Math.min(mOrigin.x, mCurrentPosition.x),
-                Math.min(mOrigin.y, mCurrentPosition.y),
-                Math.max(mOrigin.x, mCurrentPosition.x),
-                Math.max(mOrigin.y, mCurrentPosition.y));
-
-        mHost.showBand(mBounds);
-    }
-
-    /**
-     * Ends band select by removing the overlay.
-     */
-    private void endBandSelect() {
-        if (DEBUG) Log.d(TAG, "Ending band select.");
-
-        // TODO: Currently when a band select operation ends outside
-        // of an item (e.g. in the empty area between items),
-        // getPositionNearestOrigin may return an unselected item.
-        // Since the point of this code is to establish the
-        // anchor point for subsequent range operations (SHIFT+CLICK)
-        // we really want to do a better job figuring out the last
-        // item selected (and nearest to the cursor).
-        int firstSelected = mModel.getPositionNearestOrigin();
-        if (firstSelected != GridModel.NOT_SET
-                && mSelectionHelper.isSelected(mStableIds.getStableId(firstSelected))) {
-            // Establish the band selection point as range anchor. This
-            // allows touch and keyboard based selection activities
-            // to be based on the band selection anchor point.
-            mSelectionHelper.anchorRange(firstSelected);
-        }
-
-        mSelectionHelper.mergeProvisionalSelection();
-        reset();
-    }
-
-    /**
-     * @see RecyclerView.OnScrollListener
-     */
-    private void onScrolled(RecyclerView recyclerView, int dx, int dy) {
-        if (!isActive()) {
-            return;
-        }
-
-        // Adjust the y-coordinate of the origin the opposite number of pixels so that the
-        // origin remains in the same place relative to the view's items.
-        mOrigin.y -= dy;
-        resizeBand();
-    }
-
-    /**
-     * Provides functionality for BandController. Exists primarily to tests that are
-     * fully isolated from RecyclerView.
-     */
-    public static abstract class BandHost extends ScrollerCallbacks {
-        public abstract void showBand(Rect rect);
-        public abstract void hideBand();
-        public abstract void addOnScrollListener(RecyclerView.OnScrollListener listener);
-        public abstract void removeOnScrollListener(RecyclerView.OnScrollListener listener);
-        public abstract int getHeight();
-        public abstract void invalidateView();
-        public abstract Point createAbsolutePoint(Point relativePoint);
-        public abstract Rect getAbsoluteRectForChildViewAt(int index);
-        public abstract int getAdapterPositionAt(int index);
-        public abstract int getColumnCount();
-        public abstract int getChildCount();
-        public abstract int getVisibleChildCount();
-        /**
-         * @return true if the item at adapter position is attached to a view.
-         */
-        public abstract boolean hasView(int adapterPosition);
-    }
-}
diff --git a/src/com/android/documentsui/selection/ContentLock.java b/src/com/android/documentsui/selection/ContentLock.java
deleted file mode 100644
index 387e70ccc..000000000
--- a/src/com/android/documentsui/selection/ContentLock.java
+++ /dev/null
@@ -1,96 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkState;
-import static com.android.documentsui.selection.Shared.DEBUG;
-import static com.android.documentsui.selection.Shared.TAG;
-
-import androidx.annotation.MainThread;
-import androidx.annotation.Nullable;
-import android.content.Loader;
-import android.util.Log;
-
-/**
- * ContentLock provides a mechanism to block content from reloading while selection
- * activities like gesture and band selection are active. Clients using live data
- * (data loaded, for example by a {@link Loader}), should route calls to load
- * content through this lock using {@link ContentLock#runWhenUnlocked(Runnable)}.
- */
-public final class ContentLock {
-
-    private int mLocks = 0;
-    private @Nullable Runnable mCallback;
-
-    /**
-     * Increment the block count by 1
-     */
-    @MainThread
-    public synchronized void block() {
-        mLocks++;
-        if (DEBUG) Log.v(TAG, "Incremented content lock count to " + mLocks + ".");
-    }
-
-    /**
-     * Decrement the block count by 1; If no other object is trying to block and there exists some
-     * callback, that callback will be run
-     */
-    @MainThread
-    public synchronized void unblock() {
-        checkState(mLocks > 0);
-
-        mLocks--;
-        if (DEBUG) Log.v(TAG, "Decremented content lock count to " + mLocks + ".");
-
-        if (mLocks == 0 && mCallback != null) {
-            mCallback.run();
-            mCallback = null;
-        }
-    }
-
-    /**
-     * Attempts to run the given Runnable if not-locked, or else the Runnable is set to be ran next
-     * (replacing any previous set Runnables).
-     */
-    public synchronized void runWhenUnlocked(Runnable runnable) {
-        if (mLocks == 0) {
-            runnable.run();
-        } else {
-            mCallback = runnable;
-        }
-    }
-
-    /**
-     * Returns true if locked.
-     */
-    synchronized boolean isLocked() {
-        return mLocks > 0;
-    }
-
-    /**
-     * Allows other selection code to perform a precondition check asserting the state is locked.
-     */
-    final void checkLocked() {
-        checkState(isLocked());
-    }
-
-    /**
-     * Allows other selection code to perform a precondition check asserting the state is unlocked.
-     */
-    final void checkUnlocked() {
-        checkState(!isLocked());
-    }
-}
diff --git a/src/com/android/documentsui/selection/DefaultBandHost.java b/src/com/android/documentsui/selection/DefaultBandHost.java
deleted file mode 100644
index 5b24e8e92..000000000
--- a/src/com/android/documentsui/selection/DefaultBandHost.java
+++ /dev/null
@@ -1,147 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import androidx.annotation.DrawableRes;
-import android.graphics.Point;
-import android.graphics.Rect;
-import android.graphics.drawable.Drawable;
-import androidx.recyclerview.widget.GridLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.View;
-
-import com.android.documentsui.selection.BandSelectionHelper.BandHost;
-
-/**
- * RecyclerView backed {@link BandHost}.
- */
-public final class DefaultBandHost extends BandHost {
-
-    private final RecyclerView mRecView;
-    private final Drawable mBand;
-
-    private boolean mIsOverlayShown;
-
-    public DefaultBandHost(RecyclerView recView, @DrawableRes int bandOverlayId) {
-
-        checkArgument(recView != null);
-
-        mRecView = recView;
-        mBand = mRecView.getContext().getTheme().getDrawable(bandOverlayId);
-
-        checkArgument(mBand != null);
-    }
-
-    @Override
-    public int getAdapterPositionAt(int index) {
-        return mRecView.getChildAdapterPosition(mRecView.getChildAt(index));
-    }
-
-    @Override
-    public void addOnScrollListener(RecyclerView.OnScrollListener listener) {
-        mRecView.addOnScrollListener(listener);
-    }
-
-    @Override
-    public void removeOnScrollListener(RecyclerView.OnScrollListener listener) {
-        mRecView.removeOnScrollListener(listener);
-    }
-
-    @Override
-    public Point createAbsolutePoint(Point relativePoint) {
-        return new Point(relativePoint.x + mRecView.computeHorizontalScrollOffset(),
-                relativePoint.y + mRecView.computeVerticalScrollOffset());
-    }
-
-    @Override
-    public Rect getAbsoluteRectForChildViewAt(int index) {
-        final View child = mRecView.getChildAt(index);
-        final Rect childRect = new Rect();
-        child.getHitRect(childRect);
-        childRect.left += mRecView.computeHorizontalScrollOffset();
-        childRect.right += mRecView.computeHorizontalScrollOffset();
-        childRect.top += mRecView.computeVerticalScrollOffset();
-        childRect.bottom += mRecView.computeVerticalScrollOffset();
-        return childRect;
-    }
-
-    @Override
-    public int getChildCount() {
-        return mRecView.getAdapter().getItemCount();
-    }
-
-    @Override
-    public int getVisibleChildCount() {
-        return mRecView.getChildCount();
-    }
-
-    @Override
-    public int getColumnCount() {
-        RecyclerView.LayoutManager layoutManager = mRecView.getLayoutManager();
-        if (layoutManager instanceof GridLayoutManager) {
-            return ((GridLayoutManager) layoutManager).getSpanCount();
-        }
-
-        // Otherwise, it is a list with 1 column.
-        return 1;
-    }
-
-    @Override
-    public int getHeight() {
-        return mRecView.getHeight();
-    }
-
-    @Override
-    public void invalidateView() {
-        mRecView.invalidate();
-    }
-
-    @Override
-    public void runAtNextFrame(Runnable r) {
-        mRecView.postOnAnimation(r);
-    }
-
-    @Override
-    public void removeCallback(Runnable r) {
-        mRecView.removeCallbacks(r);
-    }
-
-    @Override
-    public void scrollBy(int dy) {
-        mRecView.scrollBy(0, dy);
-    }
-
-    @Override
-    public void showBand(Rect rect) {
-        mBand.setBounds(rect);
-
-        if (!mIsOverlayShown) {
-            mRecView.getOverlay().add(mBand);
-        }
-    }
-
-    @Override
-    public void hideBand() {
-        mRecView.getOverlay().remove(mBand);
-    }
-
-    @Override
-    public boolean hasView(int pos) {
-        return mRecView.findViewHolderForAdapterPosition(pos) != null;
-    }
-}
\ No newline at end of file
diff --git a/src/com/android/documentsui/selection/DefaultBandPredicate.java b/src/com/android/documentsui/selection/DefaultBandPredicate.java
deleted file mode 100644
index afbaa3361..000000000
--- a/src/com/android/documentsui/selection/DefaultBandPredicate.java
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import androidx.annotation.Nullable;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-
-/**
- * BandPredicate that consults ItemDetails, premitting band selection to start
- * when the event is not in the drag region of the item.
- */
-public final class DefaultBandPredicate extends BandPredicate {
-
-    private final ItemDetailsLookup mDetailsLookup;
-
-    public DefaultBandPredicate(ItemDetailsLookup detailsLookup) {
-        checkArgument(detailsLookup != null);
-
-        mDetailsLookup = detailsLookup;
-    }
-
-    @Override
-    public boolean canInitiate(MotionEvent e) {
-        @Nullable ItemDetails details = mDetailsLookup.getItemDetails(e);
-        return (details != null)
-            ? !details.inDragRegion(e)
-            : true;
-    }
-}
diff --git a/src/com/android/documentsui/selection/DefaultSelectionHelper.java b/src/com/android/documentsui/selection/DefaultSelectionHelper.java
deleted file mode 100644
index 0bd45a46e..000000000
--- a/src/com/android/documentsui/selection/DefaultSelectionHelper.java
+++ /dev/null
@@ -1,554 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-import static androidx.core.util.Preconditions.checkState;
-import static com.android.documentsui.selection.Shared.DEBUG;
-import static com.android.documentsui.selection.Shared.TAG;
-
-import androidx.annotation.IntDef;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.Adapter;
-import android.util.Log;
-
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-import javax.annotation.Nullable;
-
-/**
- * {@link SelectionHelper} providing support traditional multi-item selection on top
- * of {@link RecyclerView}.
- *
- * <p>The class supports running in a single-select mode, which can be enabled
- * by passing {@colde #MODE_SINGLE} to the constructor.
- */
-public final class DefaultSelectionHelper extends SelectionHelper {
-
-    public static final int MODE_MULTIPLE = 0;
-    public static final int MODE_SINGLE = 1;
-
-    @IntDef(flag = true, value = {
-            MODE_MULTIPLE,
-            MODE_SINGLE
-    })
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface SelectionMode {}
-
-    private static final int RANGE_REGULAR = 0;
-
-    /**
-     * "Provisional" selection represents a overlay on the primary selection. A provisional
-     * selection maybe be eventually added to the primary selection, or it may be abandoned.
-     *
-     * <p>E.g. BandController creates a provisional selection while a user is actively selecting
-     * items with the band. Provisionally selected items are considered to be selected in
-     * {@link Selection#contains(String)} and related methods. A provisional may be abandoned or
-     * applied by selection components (like
-     * {@link com.android.documentsui.selection.BandSelectionHelper}).
-     *
-     * <p>A provisional selection may intersect the primary selection, however clearing the
-     * provisional selection will not affect the primary selection where the two may intersect.
-     */
-    private static final int RANGE_PROVISIONAL = 1;
-    @IntDef({
-        RANGE_REGULAR,
-        RANGE_PROVISIONAL
-    })
-    @Retention(RetentionPolicy.SOURCE)
-    @interface RangeType {}
-
-    private final Selection mSelection = new Selection();
-    private final List<SelectionObserver> mObservers = new ArrayList<>(1);
-    private final RecyclerView.Adapter<?> mAdapter;
-    private final StableIdProvider mStableIds;
-    private final SelectionPredicate mSelectionPredicate;
-    private final RecyclerView.AdapterDataObserver mAdapterObserver;
-    private final RangeCallbacks mRangeCallbacks;
-    private final boolean mSingleSelect;
-
-    private @Nullable Range mRange;
-
-    /**
-     * Creates a new instance.
-     *
-     * @param mode single or multiple selection mode. In single selection mode
-     *     users can only select a single item.
-     * @param adapter {@link Adapter} for the RecyclerView this instance is coupled with.
-     * @param stableIds client supplied class providing access to stable ids.
-     * @param selectionPredicate A predicate allowing the client to disallow selection
-     *     of individual elements.
-     */
-    public DefaultSelectionHelper(
-            @SelectionMode int mode,
-            RecyclerView.Adapter<?> adapter,
-            StableIdProvider stableIds,
-            SelectionPredicate selectionPredicate) {
-
-        checkArgument(mode == MODE_SINGLE || mode == MODE_MULTIPLE);
-        checkArgument(adapter != null);
-        checkArgument(stableIds != null);
-        checkArgument(selectionPredicate != null);
-
-        mAdapter = adapter;
-        mStableIds = stableIds;
-        mSelectionPredicate = selectionPredicate;
-        mAdapterObserver = new AdapterObserver();
-        mRangeCallbacks = new RangeCallbacks();
-
-        mSingleSelect = mode == MODE_SINGLE;
-
-        mAdapter.registerAdapterDataObserver(mAdapterObserver);
-    }
-
-    @Override
-    public void addObserver(SelectionObserver callback) {
-        checkArgument(callback != null);
-        mObservers.add(callback);
-    }
-
-    @Override
-    public boolean hasSelection() {
-        return !mSelection.isEmpty();
-    }
-
-    @Override
-    public Selection getSelection() {
-        return mSelection;
-    }
-
-    @Override
-    public void copySelection(Selection dest) {
-        dest.copyFrom(mSelection);
-    }
-
-    @Override
-    public boolean isSelected(String id) {
-        return mSelection.contains(id);
-    }
-
-    @Override
-    public void restoreSelection(Selection other) {
-        setItemsSelectedQuietly(other.mSelection, true);
-        // NOTE: We intentionally don't restore provisional selection. It's provisional.
-        notifySelectionRestored();
-    }
-
-    @Override
-    public boolean setItemsSelected(Iterable<String> ids, boolean selected) {
-        boolean changed = setItemsSelectedQuietly(ids, selected);
-        notifySelectionChanged();
-        return changed;
-    }
-
-    private boolean setItemsSelectedQuietly(Iterable<String> ids, boolean selected) {
-        boolean changed = false;
-        for (String id: ids) {
-            boolean itemChanged = selected
-                    ? canSetState(id, true) && mSelection.add(id)
-                    : canSetState(id, false) && mSelection.remove(id);
-            if (itemChanged) {
-                notifyItemStateChanged(id, selected);
-            }
-            changed |= itemChanged;
-        }
-        return changed;
-    }
-
-    @Override
-    public void clearSelection() {
-        if (!hasSelection()) {
-            return;
-        }
-
-        Selection prev = clearSelectionQuietly();
-        notifySelectionCleared(prev);
-        notifySelectionChanged();
-    }
-
-    /**
-     * Clears the selection, without notifying selection listeners.
-     * Returns items in previous selection. Callers are responsible for notifying
-     * listeners about changes.
-     */
-    private Selection clearSelectionQuietly() {
-        mRange = null;
-
-        Selection prevSelection = new Selection();
-        if (hasSelection()) {
-            copySelection(prevSelection);
-            mSelection.clear();
-        }
-
-        return prevSelection;
-    }
-
-    @Override
-    public boolean select(String id) {
-        checkArgument(id != null);
-
-        if (!mSelection.contains(id)) {
-            if (!canSetState(id, true)) {
-                if (DEBUG) Log.d(TAG, "Select cancelled by selection predicate test.");
-                return false;
-            }
-
-            // Enforce single selection policy.
-            if (mSingleSelect && hasSelection()) {
-                Selection prev = clearSelectionQuietly();
-                notifySelectionCleared(prev);
-            }
-
-            mSelection.add(id);
-            notifyItemStateChanged(id, true);
-            notifySelectionChanged();
-
-            return true;
-        }
-
-        return false;
-    }
-
-    @Override
-    public boolean deselect(String id) {
-        checkArgument(id != null);
-
-        if (mSelection.contains(id)) {
-            if (!canSetState(id, false)) {
-                if (DEBUG) Log.d(TAG, "Deselect cancelled by selection predicate test.");
-                return false;
-            }
-            mSelection.remove(id);
-            notifyItemStateChanged(id, false);
-            notifySelectionChanged();
-            if (mSelection.isEmpty() && isRangeActive()) {
-                // if there's nothing in the selection and there is an active ranger it results
-                // in unexpected behavior when the user tries to start range selection: the item
-                // which the ranger 'thinks' is the already selected anchor becomes unselectable
-                endRange();
-            }
-            return true;
-        }
-
-        return false;
-    }
-
-    @Override
-    public void startRange(int pos) {
-        select(mStableIds.getStableId(pos));
-        anchorRange(pos);
-    }
-
-    @Override
-    public void extendRange(int pos) {
-        extendRange(pos, RANGE_REGULAR);
-    }
-
-    @Override
-    public void endRange() {
-        mRange = null;
-        // Clean up in case there was any leftover provisional selection
-        clearProvisionalSelection();
-    }
-
-    @Override
-    public void anchorRange(int position) {
-        checkArgument(position != RecyclerView.NO_POSITION);
-
-        // TODO: I'm not a fan of silently ignoring calls.
-        // Determine if there are any cases where method can be called
-        // w/o item already being selected. Else, tighten up the ship
-        // and make this conditional guard into a proper precondition check.
-        if (mSelection.contains(mStableIds.getStableId(position))) {
-            mRange = new Range(mRangeCallbacks, position);
-        }
-    }
-
-    @Override
-    public void extendProvisionalRange(int pos) {
-        extendRange(pos, RANGE_PROVISIONAL);
-    }
-
-    /**
-     * Sets the end point for the current range selection, started by a call to
-     * {@link #startRange(int)}. This function should only be called when a range selection
-     * is active (see {@link #isRangeActive()}. Items in the range [anchor, end] will be
-     * selected or in provisional select, depending on the type supplied. Note that if the type is
-     * provisional selection, one should do {@link #mergeProvisionalSelection()} at some
-     * point before calling on {@link #endRange()}.
-     *
-     * @param pos The new end position for the selection range.
-     * @param type The type of selection the range should utilize.
-     */
-    private void extendRange(int pos, @RangeType int type) {
-        checkState(isRangeActive(), "Range start point not set.");
-
-        mRange.extendSelection(pos, type);
-
-        // We're being lazy here notifying even when something might not have changed.
-        // To make this more correct, we'd need to update the Ranger class to return
-        // information about what has changed.
-        notifySelectionChanged();
-    }
-
-    @Override
-    public void setProvisionalSelection(Set<String> newSelection) {
-        Map<String, Boolean> delta = mSelection.setProvisionalSelection(newSelection);
-        for (Map.Entry<String, Boolean> entry: delta.entrySet()) {
-            notifyItemStateChanged(entry.getKey(), entry.getValue());
-        }
-
-        notifySelectionChanged();
-    }
-
-    @Override
-    public void mergeProvisionalSelection() {
-        mSelection.mergeProvisionalSelection();
-    }
-
-    @Override
-    public void clearProvisionalSelection() {
-        for (String id : mSelection.mProvisionalSelection) {
-            notifyItemStateChanged(id, false);
-        }
-        mSelection.clearProvisionalSelection();
-    }
-
-    @Override
-    public boolean isRangeActive() {
-        return mRange != null;
-    }
-
-    private boolean canSetState(String id, boolean nextState) {
-        return mSelectionPredicate.canSetStateForId(id, nextState);
-    }
-
-    private void onDataSetChanged() {
-        // Update the selection to remove any disappeared IDs.
-        mSelection.clearProvisionalSelection();
-        mSelection.intersect(mStableIds.getStableIds());
-        notifySelectionReset();
-
-        for (String id : mSelection) {
-            // If the underlying data set has changed, before restoring
-            // selection we must re-verify that it can be selected.
-            // Why? Because if the dataset has changed, then maybe the
-            // selectability of an item has changed.
-            if (!canSetState(id, true)) {
-                deselect(id);
-            } else {
-                int lastListener = mObservers.size() - 1;
-                for (int i = lastListener; i >= 0; i--) {
-                    mObservers.get(i).onItemStateChanged(id, true);
-                }
-            }
-        }
-        notifySelectionChanged();
-    }
-
-    private void onDataSetItemRangeInserted(int startPosition, int itemCount) {
-        mSelection.clearProvisionalSelection();
-    }
-
-    private void onDataSetItemRangeRemoved(int startPosition, int itemCount) {
-        checkArgument(startPosition >= 0);
-        checkArgument(itemCount > 0);
-
-        mSelection.clearProvisionalSelection();
-
-        // Remove any disappeared IDs from the selection.
-        //
-        // Ideally there could be a cheaper approach, checking
-        // each position individually, but since the source of
-        // truth for stable ids (StableIdProvider) probably
-        // it-self no-longer knows about the positions in question
-        // we fall back to the sledge hammer approach.
-        mSelection.intersect(mStableIds.getStableIds());
-    }
-
-    /**
-     * Notifies registered listeners when the selection status of a single item
-     * (identified by {@code position}) changes.
-     */
-    private void notifyItemStateChanged(String id, boolean selected) {
-        checkArgument(id != null);
-
-        int lastListenerIndex = mObservers.size() - 1;
-        for (int i = lastListenerIndex; i >= 0; i--) {
-            mObservers.get(i).onItemStateChanged(id, selected);
-        }
-
-        int position = mStableIds.getPosition(id);
-        if (DEBUG) Log.d(TAG, "ITEM " + id + " CHANGED at pos: " + position);
-
-        if (position >= 0) {
-            mAdapter.notifyItemChanged(position, SelectionHelper.SELECTION_CHANGED_MARKER);
-        } else {
-            Log.w(TAG, "Item change notification received for unknown item: " + id);
-        }
-    }
-
-    private void notifySelectionCleared(Selection selection) {
-        for (String id: selection.mSelection) {
-            notifyItemStateChanged(id, false);
-        }
-        for (String id: selection.mProvisionalSelection) {
-            notifyItemStateChanged(id, false);
-        }
-    }
-
-    /**
-     * Notifies registered listeners when the selection has changed. This
-     * notification should be sent only once a full series of changes
-     * is complete, e.g. clearingSelection, or updating the single
-     * selection from one item to another.
-     */
-    private void notifySelectionChanged() {
-        int lastListenerIndex = mObservers.size() - 1;
-        for (int i = lastListenerIndex; i >= 0; i--) {
-            mObservers.get(i).onSelectionChanged();
-        }
-    }
-
-    private void notifySelectionRestored() {
-        int lastListenerIndex = mObservers.size() - 1;
-        for (int i = lastListenerIndex; i >= 0; i--) {
-            mObservers.get(i).onSelectionRestored();
-        }
-    }
-
-    private void notifySelectionReset() {
-        int lastListenerIndex = mObservers.size() - 1;
-        for (int i = lastListenerIndex; i >= 0; i--) {
-            mObservers.get(i).onSelectionReset();
-        }
-    }
-
-    private void updateForRange(int begin, int end, boolean selected, @RangeType int type) {
-        switch (type) {
-            case RANGE_REGULAR:
-                updateForRegularRange(begin, end, selected);
-                break;
-            case RANGE_PROVISIONAL:
-                updateForProvisionalRange(begin, end, selected);
-                break;
-            default:
-                throw new IllegalArgumentException("Invalid range type: " + type);
-        }
-    }
-
-    private void updateForRegularRange(int begin, int end, boolean selected) {
-        checkArgument(end >= begin);
-
-        for (int i = begin; i <= end; i++) {
-            String id = mStableIds.getStableId(i);
-            if (id == null) {
-                continue;
-            }
-
-            if (selected) {
-                select(id);
-            } else {
-                deselect(id);
-            }
-        }
-    }
-
-    private void updateForProvisionalRange(int begin, int end, boolean selected) {
-        checkArgument(end >= begin);
-
-        for (int i = begin; i <= end; i++) {
-            String id = mStableIds.getStableId(i);
-            if (id == null) {
-                continue;
-            }
-
-            boolean changedState = false;
-            if (selected) {
-                boolean canSelect = canSetState(id, true);
-                if (canSelect && !mSelection.mSelection.contains(id)) {
-                    mSelection.mProvisionalSelection.add(id);
-                    changedState = true;
-                }
-            } else {
-                mSelection.mProvisionalSelection.remove(id);
-                changedState = true;
-            }
-
-            // Only notify item callbacks when something's state is actually changed in provisional
-            // selection.
-            if (changedState) {
-                notifyItemStateChanged(id, selected);
-            }
-        }
-
-        notifySelectionChanged();
-    }
-
-    private final class AdapterObserver extends RecyclerView.AdapterDataObserver {
-        @Override
-        public void onChanged() {
-            onDataSetChanged();
-        }
-
-        @Override
-        public void onItemRangeChanged(
-                int startPosition, int itemCount, Object payload) {
-            // No change in position. Ignore, since we assume
-            // selection is a user driven activity. So changes
-            // in properties of items shouldn't result in a
-            // change of selection.
-        }
-
-        @Override
-        public void onItemRangeInserted(int startPosition, int itemCount) {
-            onDataSetItemRangeInserted(startPosition, itemCount);
-        }
-
-        @Override
-        public void onItemRangeRemoved(int startPosition, int itemCount) {
-            onDataSetItemRangeRemoved(startPosition, itemCount);
-        }
-
-        @Override
-        public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
-            throw new UnsupportedOperationException();
-        }
-    }
-
-    private final class RangeCallbacks extends Range.Callbacks {
-        @Override
-        void updateForRange(int begin, int end, boolean selected, int type) {
-            switch (type) {
-                case RANGE_REGULAR:
-                    updateForRegularRange(begin, end, selected);
-                    break;
-                case RANGE_PROVISIONAL:
-                    updateForProvisionalRange(begin, end, selected);
-                    break;
-                default:
-                    throw new IllegalArgumentException(
-                            "Invalid range type: " + type);
-            }
-        }
-    }
-}
diff --git a/src/com/android/documentsui/selection/GestureRouter.java b/src/com/android/documentsui/selection/GestureRouter.java
deleted file mode 100644
index be143c45b..000000000
--- a/src/com/android/documentsui/selection/GestureRouter.java
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkNotNull;
-
-import androidx.annotation.Nullable;
-import android.view.GestureDetector.OnDoubleTapListener;
-import android.view.GestureDetector.OnGestureListener;
-import android.view.GestureDetector.SimpleOnGestureListener;
-import android.view.MotionEvent;
-
-/**
- * GestureRouter is responsible for routing gestures detected by a GestureDetector
- * to registered handlers. The primary function is to divide events by tool-type
- * allowing handlers to cleanly implement tool-type specific policies.
- */
-public final class GestureRouter<T extends OnGestureListener & OnDoubleTapListener>
-        implements OnGestureListener, OnDoubleTapListener {
-
-    private final ToolHandlerRegistry<T> mDelegates;
-
-    public GestureRouter(T defaultDelegate) {
-        checkNotNull(defaultDelegate);
-        mDelegates = new ToolHandlerRegistry<>(defaultDelegate);
-    }
-
-    public GestureRouter() {
-        this((T) new SimpleOnGestureListener());
-    }
-
-    /**
-     * @param toolType
-     * @param delegate the delegate, or null to unregister.
-     */
-    public void register(int toolType, @Nullable T delegate) {
-        mDelegates.set(toolType, delegate);
-    }
-
-    @Override
-    public boolean onSingleTapConfirmed(MotionEvent e) {
-        return mDelegates.get(e).onSingleTapConfirmed(e);
-    }
-
-    @Override
-    public boolean onDoubleTap(MotionEvent e) {
-        return mDelegates.get(e).onDoubleTap(e);
-    }
-
-    @Override
-    public boolean onDoubleTapEvent(MotionEvent e) {
-        return mDelegates.get(e).onDoubleTapEvent(e);
-    }
-
-    @Override
-    public boolean onDown(MotionEvent e) {
-        return mDelegates.get(e).onDown(e);
-    }
-
-    @Override
-    public void onShowPress(MotionEvent e) {
-        mDelegates.get(e).onShowPress(e);
-    }
-
-    @Override
-    public boolean onSingleTapUp(MotionEvent e) {
-        return mDelegates.get(e).onSingleTapUp(e);
-    }
-
-    @Override
-    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
-        return mDelegates.get(e2).onScroll(e1, e2, distanceX, distanceY);
-    }
-
-    @Override
-    public void onLongPress(MotionEvent e) {
-        mDelegates.get(e).onLongPress(e);
-    }
-
-    @Override
-    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
-        return mDelegates.get(e2).onFling(e1, e2, velocityX, velocityY);
-    }
-}
diff --git a/src/com/android/documentsui/selection/GestureSelectionHelper.java b/src/com/android/documentsui/selection/GestureSelectionHelper.java
deleted file mode 100644
index 21f9b09ef..000000000
--- a/src/com/android/documentsui/selection/GestureSelectionHelper.java
+++ /dev/null
@@ -1,350 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-import static androidx.core.util.Preconditions.checkState;
-
-import android.graphics.Point;
-import android.os.Build;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.VisibleForTesting;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener;
-
-import android.util.Log;
-import android.view.MotionEvent;
-import android.view.View;
-
-import com.android.documentsui.selection.ViewAutoScroller.ScrollHost;
-import com.android.documentsui.selection.ViewAutoScroller.ScrollerCallbacks;
-
-/**
- * GestureSelectionHelper provides logic that interprets a combination
- * of motions and gestures in order to provide gesture driven selection support
- * when used in conjunction with RecyclerView and other classes in the ReyclerView
- * selection support package.
- */
-public final class GestureSelectionHelper extends ScrollHost implements OnItemTouchListener {
-
-    private static final String TAG = "GestureSelectionHelper";
-
-    private final SelectionHelper mSelectionMgr;
-    private final Runnable mScroller;
-    private final ViewDelegate mView;
-    private final ContentLock mLock;
-    private final ItemDetailsLookup mItemLookup;
-
-    private int mLastTouchedItemPosition = RecyclerView.NO_POSITION;
-    private boolean mStarted = false;
-    private Point mLastInterceptedPoint;
-
-    /**
-     * See {@link #create(SelectionHelper, RecyclerView, ContentLock)} for convenience
-     * method.
-     */
-    @VisibleForTesting
-    GestureSelectionHelper(
-            SelectionHelper selectionHelper,
-            ViewDelegate view,
-            ContentLock lock,
-            ItemDetailsLookup itemLookup) {
-
-        checkArgument(selectionHelper != null);
-        checkArgument(view != null);
-        checkArgument(lock != null);
-        checkArgument(itemLookup != null);
-
-        mSelectionMgr = selectionHelper;
-        mView = view;
-        mLock = lock;
-        mItemLookup = itemLookup;
-
-        mScroller = new ViewAutoScroller(this, mView);
-    }
-
-    /**
-     * Explicitly kicks off a gesture multi-select.
-     *
-     * @return true if started.
-     */
-    public void start() {
-        checkState(!mStarted);
-        // See: b/70518185. It appears start() is being called via onLongPress
-        // even though we never received an intial handleInterceptedDownEvent
-        // where we would usually initialize mLastStartedItemPos.
-        if (mLastTouchedItemPosition == RecyclerView.NO_POSITION) {
-            Log.w(TAG, "Illegal state. Can't start without valid mLastStartedItemPos.");
-            return;
-        }
-
-        // Partner code in MotionInputHandler ensures items
-        // are selected and range established prior to
-        // start being called.
-        // Verify the truth of that statement here
-        // to make the implicit coupling less of a time bomb.
-        checkState(mSelectionMgr.isRangeActive());
-
-        mLock.checkUnlocked();
-
-        mStarted = true;
-        mLock.block();
-    }
-
-    @Override
-    public boolean onInterceptTouchEvent(RecyclerView unused, MotionEvent e) {
-        if (MotionEvents.isMouseEvent(e)) {
-            if (Shared.DEBUG) Log.w(TAG, "Unexpected Mouse event. Check configuration.");
-        }
-
-        // TODO(b/109808552): It seems that mLastStartedItemPos should likely be set as a method
-        // parameter in start().
-        if (e.getActionMasked() == MotionEvent.ACTION_DOWN) {
-            if (mItemLookup.getItemDetails(e) != null) {
-                mLastTouchedItemPosition = mView.getItemUnder(e);
-            }
-        }
-
-        // See handleTouch(MotionEvent) javadoc for explanation as to why this is correct.
-        return handleTouch(e);
-    }
-
-    @Override
-    /** @hide */
-    public void onTouchEvent(@NonNull RecyclerView unused, @NonNull MotionEvent e) {
-        // See handleTouch(MotionEvent) javadoc for explanation as to why this is correct.
-        handleTouch(e);
-    }
-
-    /**
-     * If selection has started, will handle all appropriate types of MotionEvents and will return
-     * true if this OnItemTouchListener should start intercepting the rest of the MotionEvents.
-     *
-     * <p>This code, and the fact that this method is used by both OnInterceptTouchEvent and
-     * OnTouchEvent, is correct and valid because:
-     * <ol>
-     * <li>MotionEvents that aren't ACTION_DOWN are only ever passed to either onInterceptTouchEvent
-     * or onTouchEvent; never to both.  The MotionEvents we are handling in this method are not
-     * ACTION_DOWN, and therefore, its appropriate that both the onInterceptTouchEvent and
-     * onTouchEvent code paths cross this method.
-     * <li>This method returns true when we want to intercept MotionEvents.  OnInterceptTouchEvent
-     * uses that information to determine its own return, and OnMotionEvent doesn't have a return
-     * so this methods return value is irrelevant to it.
-     * </ol>
-     */
-    private boolean handleTouch(MotionEvent e) {
-        if (!mStarted) {
-            return false;
-        }
-
-        switch (e.getActionMasked()) {
-            case MotionEvent.ACTION_MOVE:
-                handleMoveEvent(e);
-                return true;
-            case MotionEvent.ACTION_UP:
-                handleUpEvent();
-                return true;
-            case MotionEvent.ACTION_CANCEL:
-                handleCancelEvent();
-                return true;
-        }
-
-        return false;
-    }
-
-    @Override
-    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
-    }
-
-    // Called when ACTION_UP event is to be handled.
-    // Essentially, since this means all gesture movement is over, reset everything and apply
-    // provisional selection.
-    private void handleUpEvent() {
-        mSelectionMgr.mergeProvisionalSelection();
-        endSelection();
-        if (mLastTouchedItemPosition != RecyclerView.NO_POSITION) {
-            mSelectionMgr.startRange(mLastTouchedItemPosition);
-        }
-    }
-
-    // Called when ACTION_CANCEL event is to be handled.
-    // This means this gesture selection is aborted, so reset everything and abandon provisional
-    // selection.
-    private void handleCancelEvent() {
-        mSelectionMgr.clearProvisionalSelection();
-        endSelection();
-    }
-
-    private void endSelection() {
-        checkState(mStarted);
-
-        mLastTouchedItemPosition = RecyclerView.NO_POSITION;
-        mStarted = false;
-        mLock.unblock();
-    }
-
-    // Call when an intercepted ACTION_MOVE event is passed down.
-    // At this point, we are sure user wants to gesture multi-select.
-    private void handleMoveEvent(MotionEvent e) {
-        mLastInterceptedPoint = MotionEvents.getOrigin(e);
-
-        int lastGlidedItemPos = mView.getLastGlidedItemPosition(e);
-        if (lastGlidedItemPos != RecyclerView.NO_POSITION) {
-            doGestureMultiSelect(lastGlidedItemPos);
-        }
-        scrollIfNecessary();
-    }
-
-    // It's possible for events to go over the top/bottom of the RecyclerView.
-    // We want to get a Y-coordinate within the RecyclerView so we can find the childView underneath
-    // correctly.
-    private static float getInboundY(float max, float y) {
-        if (y < 0f) {
-            return 0f;
-        } else if (y > max) {
-            return max;
-        }
-        return y;
-    }
-
-    /* Given the end position, select everything in-between.
-     * @param endPos  The adapter position of the end item.
-     */
-    private void doGestureMultiSelect(int endPos) {
-        mSelectionMgr.extendProvisionalRange(endPos);
-    }
-
-    private void scrollIfNecessary() {
-        mScroller.run();
-    }
-
-    @Override
-    public Point getCurrentPosition() {
-        return mLastInterceptedPoint;
-    }
-
-    @Override
-    public int getViewHeight() {
-        return mView.getHeight();
-    }
-
-    @Override
-    public boolean isActive() {
-        return mStarted && mSelectionMgr.hasSelection();
-    }
-
-    /**
-     * Returns a new instance of GestureSelectionHelper, wrapping the
-     * RecyclerView in a test friendly wrapper.
-     */
-    public static GestureSelectionHelper create(
-            SelectionHelper selectionMgr,
-            RecyclerView recycler,
-            ContentLock lock,
-            ItemDetailsLookup itemLookup) {
-
-        return new GestureSelectionHelper(
-                selectionMgr, new RecyclerViewDelegate(recycler), lock, itemLookup);
-    }
-
-    @VisibleForTesting
-    static abstract class ViewDelegate extends ScrollerCallbacks {
-        abstract int getHeight();
-
-        abstract int getItemUnder(MotionEvent e);
-
-        abstract int getLastGlidedItemPosition(MotionEvent e);
-    }
-
-    @VisibleForTesting
-    static final class RecyclerViewDelegate extends ViewDelegate {
-
-        private final RecyclerView mView;
-
-        RecyclerViewDelegate(RecyclerView view) {
-            checkArgument(view != null);
-            mView = view;
-        }
-
-        @Override
-        int getHeight() {
-            return mView.getHeight();
-        }
-
-        @Override
-        int getItemUnder(MotionEvent e) {
-            View child = mView.findChildViewUnder(e.getX(), e.getY());
-            return child != null
-                    ? mView.getChildAdapterPosition(child)
-                    : RecyclerView.NO_POSITION;
-        }
-
-        @Override
-        int getLastGlidedItemPosition(MotionEvent e) {
-            // If user has moved his pointer to the bottom-right empty pane (ie. to the right of the
-            // last item of the recycler view), we would want to set that as the currentItemPos
-            View lastItem = mView.getLayoutManager()
-                    .getChildAt(mView.getLayoutManager().getChildCount() - 1);
-            int direction =
-                    mView.getContext().getResources().getConfiguration().getLayoutDirection();
-            final boolean pastLastItem = isPastLastItem(lastItem.getTop(),
-                    lastItem.getLeft(),
-                    lastItem.getRight(),
-                    e,
-                    direction);
-
-            // Since views get attached & detached from RecyclerView,
-            // {@link LayoutManager#getChildCount} can return a different number from the actual
-            // number
-            // of items in the adapter. Using the adapter is the for sure way to get the actual last
-            // item position.
-            final float inboundY = getInboundY(mView.getHeight(), e.getY());
-            return (pastLastItem) ? mView.getAdapter().getItemCount() - 1
-                    : mView.getChildAdapterPosition(mView.findChildViewUnder(e.getX(), inboundY));
-        }
-
-        /*
-         * Check to see if MotionEvent if past a particular item, i.e. to the right or to the bottom
-         * of the item.
-         * For RTL, it would to be to the left or to the bottom of the item.
-         */
-        @VisibleForTesting
-        static boolean isPastLastItem(int top, int left, int right, MotionEvent e, int direction) {
-            if (direction == View.LAYOUT_DIRECTION_LTR) {
-                return e.getX() > right && e.getY() > top;
-            } else {
-                return e.getX() < left && e.getY() > top;
-            }
-        }
-
-        @Override
-        public void scrollBy(int dy) {
-            mView.scrollBy(0, dy);
-        }
-
-        @Override
-        public void runAtNextFrame(Runnable r) {
-            mView.postOnAnimation(r);
-        }
-
-        @Override
-        public void removeCallback(Runnable r) {
-            mView.removeCallbacks(r);
-        }
-    }
-}
diff --git a/src/com/android/documentsui/selection/GridModel.java b/src/com/android/documentsui/selection/GridModel.java
deleted file mode 100644
index feca271ab..000000000
--- a/src/com/android/documentsui/selection/GridModel.java
+++ /dev/null
@@ -1,728 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-import static com.android.documentsui.base.SharedMinimal.DEBUG;
-
-import android.graphics.Point;
-import android.graphics.Rect;
-import androidx.annotation.VisibleForTesting;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.OnScrollListener;
-import android.util.Log;
-import android.util.SparseArray;
-import android.util.SparseBooleanArray;
-import android.util.SparseIntArray;
-
-import com.android.documentsui.selection.BandSelectionHelper.BandHost;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-import com.android.documentsui.selection.SelectionHelper.StableIdProvider;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-/**
- * Provides a band selection item model for views within a RecyclerView. This class queries the
- * RecyclerView to determine where its items are placed; then, once band selection is underway,
- * it alerts listeners of which items are covered by the selections.
- */
-final class GridModel {
-
-    // Magical value indicating that a value has not been previously set. primitive null :)
-    static final int NOT_SET = -1;
-
-    // Enum values used to determine the corner at which the origin is located within the
-    private static final int UPPER = 0x00;
-    private static final int LOWER = 0x01;
-    private static final int LEFT = 0x00;
-    private static final int RIGHT = 0x02;
-    private static final int UPPER_LEFT = UPPER | LEFT;
-    private static final int UPPER_RIGHT = UPPER | RIGHT;
-    private static final int LOWER_LEFT = LOWER | LEFT;
-    private static final int LOWER_RIGHT = LOWER | RIGHT;
-
-    private final BandHost mHost;
-    private final StableIdProvider mStableIds;
-    private final SelectionPredicate mSelectionPredicate;
-
-    private final List<SelectionObserver> mOnSelectionChangedListeners =
-            new ArrayList<>();
-
-    // Map from the x-value of the left side of a SparseBooleanArray of adapter positions, keyed
-    // by their y-offset. For example, if the first column of the view starts at an x-value of 5,
-    // mColumns.get(5) would return an array of positions in that column. Within that array, the
-    // value for key y is the adapter position for the item whose y-offset is y.
-    private final SparseArray<SparseIntArray> mColumns = new SparseArray<>();
-
-    // List of limits along the x-axis (columns).
-    // This list is sorted from furthest left to furthest right.
-    private final List<Limits> mColumnBounds = new ArrayList<>();
-
-    // List of limits along the y-axis (rows). Note that this list only contains items which
-    // have been in the viewport.
-    private final List<Limits> mRowBounds = new ArrayList<>();
-
-    // The adapter positions which have been recorded so far.
-    private final SparseBooleanArray mKnownPositions = new SparseBooleanArray();
-
-    // Array passed to registered OnSelectionChangedListeners. One array is created and reused
-    // throughout the lifetime of the object.
-    private final Set<String> mSelection = new HashSet<>();
-
-    // The current pointer (in absolute positioning from the top of the view).
-    private Point mPointer = null;
-
-    // The bounds of the band selection.
-    private RelativePoint mRelativeOrigin;
-    private RelativePoint mRelativePointer;
-
-    private boolean mIsActive;
-
-    // Tracks where the band select originated from. This is used to determine where selections
-    // should expand from when Shift+click is used.
-    private int mPositionNearestOrigin = NOT_SET;
-
-    private final OnScrollListener mScrollListener;
-
-    GridModel(
-            BandHost host,
-            StableIdProvider stableIds,
-            SelectionPredicate selectionPredicate) {
-
-        mHost = host;
-        mStableIds = stableIds;
-        mSelectionPredicate = selectionPredicate;
-
-        mScrollListener = new OnScrollListener() {
-            @Override
-            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
-                GridModel.this.onScrolled(recyclerView, dx, dy);
-            }
-        };
-
-        mHost.addOnScrollListener(mScrollListener);
-    }
-
-    /**
-     * Stops listening to the view's scrolls. Call this function before discarding a
-     * GridModel object to prevent memory leaks.
-     */
-    void stopListening() {
-        mHost.removeOnScrollListener(mScrollListener);
-    }
-
-    /**
-     * Start a band select operation at the given point.
-     * @param relativeOrigin The origin of the band select operation, relative to the viewport.
-     *     For example, if the view is scrolled to the bottom, the top-left of the viewport
-     *     would have a relative origin of (0, 0), even though its absolute point has a higher
-     *     y-value.
-     */
-    void startCapturing(Point relativeOrigin) {
-        recordVisibleChildren();
-        if (isEmpty()) {
-            // The selection band logic works only if there is at least one visible child.
-            return;
-        }
-
-        mIsActive = true;
-        mPointer = mHost.createAbsolutePoint(relativeOrigin);
-        mRelativeOrigin = new RelativePoint(mPointer);
-        mRelativePointer = new RelativePoint(mPointer);
-        computeCurrentSelection();
-        notifySelectionChanged();
-    }
-
-    /**
-     * Ends the band selection.
-     */
-    void stopCapturing() {
-        mIsActive = false;
-    }
-
-    /**
-     * Resizes the selection by adjusting the pointer (i.e., the corner of the selection
-     * opposite the origin.
-     * @param relativePointer The pointer (opposite of the origin) of the band select operation,
-     *     relative to the viewport. For example, if the view is scrolled to the bottom, the
-     *     top-left of the viewport would have a relative origin of (0, 0), even though its
-     *     absolute point has a higher y-value.
-     */
-    @VisibleForTesting
-    void resizeSelection(Point relativePointer) {
-        mPointer = mHost.createAbsolutePoint(relativePointer);
-        updateModel();
-    }
-
-    /**
-     * @return The adapter position for the item nearest the origin corresponding to the latest
-     *         band select operation, or NOT_SET if the selection did not cover any items.
-     */
-    int getPositionNearestOrigin() {
-        return mPositionNearestOrigin;
-    }
-
-    private void onScrolled(RecyclerView recyclerView, int dx, int dy) {
-        if (!mIsActive) {
-            return;
-        }
-
-        mPointer.x += dx;
-        mPointer.y += dy;
-        recordVisibleChildren();
-        updateModel();
-    }
-
-    /**
-     * Queries the view for all children and records their location metadata.
-     */
-    private void recordVisibleChildren() {
-        for (int i = 0; i < mHost.getVisibleChildCount(); i++) {
-            int adapterPosition = mHost.getAdapterPositionAt(i);
-            // Sometimes the view is not attached, as we notify the multi selection manager
-            // synchronously, while views are attached asynchronously. As a result items which
-            // are in the adapter may not actually have a corresponding view (yet).
-            if (mHost.hasView(adapterPosition) &&
-                    mSelectionPredicate.canSetStateAtPosition(adapterPosition, true) &&
-                    !mKnownPositions.get(adapterPosition)) {
-                mKnownPositions.put(adapterPosition, true);
-                recordItemData(mHost.getAbsoluteRectForChildViewAt(i), adapterPosition);
-            }
-        }
-    }
-
-    /**
-     * Checks if there are any recorded children.
-     */
-    private boolean isEmpty() {
-        return mColumnBounds.size() == 0 || mRowBounds.size() == 0;
-    }
-
-    /**
-     * Updates the limits lists and column map with the given item metadata.
-     * @param absoluteChildRect The absolute rectangle for the child view being processed.
-     * @param adapterPosition The position of the child view being processed.
-     */
-    private void recordItemData(Rect absoluteChildRect, int adapterPosition) {
-        if (mColumnBounds.size() != mHost.getColumnCount()) {
-            // If not all x-limits have been recorded, record this one.
-            recordLimits(
-                    mColumnBounds, new Limits(absoluteChildRect.left, absoluteChildRect.right));
-        }
-
-        recordLimits(mRowBounds, new Limits(absoluteChildRect.top, absoluteChildRect.bottom));
-
-        SparseIntArray columnList = mColumns.get(absoluteChildRect.left);
-        if (columnList == null) {
-            columnList = new SparseIntArray();
-            mColumns.put(absoluteChildRect.left, columnList);
-        }
-        columnList.put(absoluteChildRect.top, adapterPosition);
-    }
-
-    /**
-     * Ensures limits exists within the sorted list limitsList, and adds it to the list if it
-     * does not exist.
-     */
-    private void recordLimits(List<Limits> limitsList, Limits limits) {
-        int index = Collections.binarySearch(limitsList, limits);
-        if (index < 0) {
-            limitsList.add(~index, limits);
-        }
-    }
-
-    /**
-     * Handles a moved pointer; this function determines whether the pointer movement resulted
-     * in a selection change and, if it has, notifies listeners of this change.
-     */
-    private void updateModel() {
-        RelativePoint old = mRelativePointer;
-        mRelativePointer = new RelativePoint(mPointer);
-        if (old != null && mRelativePointer.equals(old)) {
-            return;
-        }
-
-        computeCurrentSelection();
-        notifySelectionChanged();
-    }
-
-    /**
-     * Computes the currently-selected items.
-     */
-    private void computeCurrentSelection() {
-        if (areItemsCoveredByBand(mRelativePointer, mRelativeOrigin)) {
-            updateSelection(computeBounds());
-        } else {
-            mSelection.clear();
-            mPositionNearestOrigin = NOT_SET;
-        }
-    }
-
-    /**
-     * Notifies all listeners of a selection change. Note that this function simply passes
-     * mSelection, so computeCurrentSelection() should be called before this
-     * function.
-     */
-    private void notifySelectionChanged() {
-        for (SelectionObserver listener : mOnSelectionChangedListeners) {
-            listener.onSelectionChanged(mSelection);
-        }
-    }
-
-    /**
-     * @param rect Rectangle including all covered items.
-     */
-    private void updateSelection(Rect rect) {
-        int columnStart =
-                Collections.binarySearch(mColumnBounds, new Limits(rect.left, rect.left));
-
-        checkArgument(columnStart >= 0, "Rect doesn't intesect any known column.");
-
-        int columnEnd = columnStart;
-
-        for (int i = columnStart; i < mColumnBounds.size()
-                && mColumnBounds.get(i).lowerLimit <= rect.right; i++) {
-            columnEnd = i;
-        }
-
-        int rowStart = Collections.binarySearch(mRowBounds, new Limits(rect.top, rect.top));
-        if (rowStart < 0) {
-            mPositionNearestOrigin = NOT_SET;
-            return;
-        }
-
-        int rowEnd = rowStart;
-        for (int i = rowStart; i < mRowBounds.size()
-                && mRowBounds.get(i).lowerLimit <= rect.bottom; i++) {
-            rowEnd = i;
-        }
-
-        updateSelection(columnStart, columnEnd, rowStart, rowEnd);
-    }
-
-    /**
-     * Computes the selection given the previously-computed start- and end-indices for each
-     * row and column.
-     */
-    private void updateSelection(
-            int columnStartIndex, int columnEndIndex, int rowStartIndex, int rowEndIndex) {
-
-        if (DEBUG) {
-            Log.d(BandSelectionHelper.TAG, String.format(
-                    "updateSelection: %d, %d, %d, %d",
-                    columnStartIndex, columnEndIndex, rowStartIndex, rowEndIndex));
-        }
-
-        mSelection.clear();
-        for (int column = columnStartIndex; column <= columnEndIndex; column++) {
-            SparseIntArray items = mColumns.get(mColumnBounds.get(column).lowerLimit);
-            for (int row = rowStartIndex; row <= rowEndIndex; row++) {
-                // The default return value for SparseIntArray.get is 0, which is a valid
-                // position. Use a sentry value to prevent erroneously selecting item 0.
-                final int rowKey = mRowBounds.get(row).lowerLimit;
-                int position = items.get(rowKey, NOT_SET);
-                if (position != NOT_SET) {
-                    String id = mStableIds.getStableId(position);
-                    if (id != null) {
-                        // The adapter inserts items for UI layout purposes that aren't
-                        // associated with files. Those will have a null model ID.
-                        // Don't select them.
-                        if (canSelect(id)) {
-                            mSelection.add(id);
-                        }
-                    }
-                    if (isPossiblePositionNearestOrigin(column, columnStartIndex, columnEndIndex,
-                            row, rowStartIndex, rowEndIndex)) {
-                        // If this is the position nearest the origin, record it now so that it
-                        // can be returned by endSelection() later.
-                        mPositionNearestOrigin = position;
-                    }
-                }
-            }
-        }
-    }
-
-    private boolean canSelect(String id) {
-        return mSelectionPredicate.canSetStateForId(id, true);
-    }
-
-    /**
-     * @return Returns true if the position is the nearest to the origin, or, in the case of the
-     *     lower-right corner, whether it is possible that the position is the nearest to the
-     *     origin. See comment below for reasoning for this special case.
-     */
-    private boolean isPossiblePositionNearestOrigin(int columnIndex, int columnStartIndex,
-            int columnEndIndex, int rowIndex, int rowStartIndex, int rowEndIndex) {
-        int corner = computeCornerNearestOrigin();
-        switch (corner) {
-            case UPPER_LEFT:
-                return columnIndex == columnStartIndex && rowIndex == rowStartIndex;
-            case UPPER_RIGHT:
-                return columnIndex == columnEndIndex && rowIndex == rowStartIndex;
-            case LOWER_LEFT:
-                return columnIndex == columnStartIndex && rowIndex == rowEndIndex;
-            case LOWER_RIGHT:
-                // Note that in some cases, the last row will not have as many items as there
-                // are columns (e.g., if there are 4 items and 3 columns, the second row will
-                // only have one item in the first column). This function is invoked for each
-                // position from left to right, so return true for any position in the bottom
-                // row and only the right-most position in the bottom row will be recorded.
-                return rowIndex == rowEndIndex;
-            default:
-                throw new RuntimeException("Invalid corner type.");
-        }
-    }
-
-    /**
-     * Listener for changes in which items have been band selected.
-     */
-    public static abstract class SelectionObserver {
-        abstract void onSelectionChanged(Set<String> updatedSelection);
-    }
-
-    void addOnSelectionChangedListener(SelectionObserver listener) {
-        mOnSelectionChangedListeners.add(listener);
-    }
-
-    /**
-     * Called when {@link BandSelectionHelper} is finished with a GridModel.
-     */
-    void onDestroy() {
-        mOnSelectionChangedListeners.clear();
-        stopListening();
-    }
-
-    /**
-     * Limits of a view item. For example, if an item's left side is at x-value 5 and its right side
-     * is at x-value 10, the limits would be from 5 to 10. Used to record the left- and right sides
-     * of item columns and the top- and bottom sides of item rows so that it can be determined
-     * whether the pointer is located within the bounds of an item.
-     */
-    private static class Limits implements Comparable<Limits> {
-        int lowerLimit;
-        int upperLimit;
-
-        Limits(int lowerLimit, int upperLimit) {
-            this.lowerLimit = lowerLimit;
-            this.upperLimit = upperLimit;
-        }
-
-        @Override
-        public int compareTo(Limits other) {
-            return lowerLimit - other.lowerLimit;
-        }
-
-        @Override
-        public int hashCode() {
-            return lowerLimit ^ upperLimit;
-        }
-
-        @Override
-        public boolean equals(Object other) {
-            if (!(other instanceof Limits)) {
-                return false;
-            }
-
-            return ((Limits) other).lowerLimit == lowerLimit &&
-                    ((Limits) other).upperLimit == upperLimit;
-        }
-
-        @Override
-        public String toString() {
-            return "(" + lowerLimit + ", " + upperLimit + ")";
-        }
-    }
-
-    /**
-     * The location of a coordinate relative to items. This class represents a general area of the
-     * view as it relates to band selection rather than an explicit point. For example, two
-     * different points within an item are considered to have the same "location" because band
-     * selection originating within the item would select the same items no matter which point
-     * was used. Same goes for points between items as well as those at the very beginning or end
-     * of the view.
-     *
-     * Tracking a coordinate (e.g., an x-value) as a CoordinateLocation instead of as an int has the
-     * advantage of tying the value to the Limits of items along that axis. This allows easy
-     * selection of items within those Limits as opposed to a search through every item to see if a
-     * given coordinate value falls within those Limits.
-     */
-    private static class RelativeCoordinate
-            implements Comparable<RelativeCoordinate> {
-        /**
-         * Location describing points after the last known item.
-         */
-        static final int AFTER_LAST_ITEM = 0;
-
-        /**
-         * Location describing points before the first known item.
-         */
-        static final int BEFORE_FIRST_ITEM = 1;
-
-        /**
-         * Location describing points between two items.
-         */
-        static final int BETWEEN_TWO_ITEMS = 2;
-
-        /**
-         * Location describing points within the limits of one item.
-         */
-        static final int WITHIN_LIMITS = 3;
-
-        /**
-         * The type of this coordinate, which is one of AFTER_LAST_ITEM, BEFORE_FIRST_ITEM,
-         * BETWEEN_TWO_ITEMS, or WITHIN_LIMITS.
-         */
-        final int type;
-
-        /**
-         * The limits before the coordinate; only populated when type == WITHIN_LIMITS or type ==
-         * BETWEEN_TWO_ITEMS.
-         */
-        Limits limitsBeforeCoordinate;
-
-        /**
-         * The limits after the coordinate; only populated when type == BETWEEN_TWO_ITEMS.
-         */
-        Limits limitsAfterCoordinate;
-
-        // Limits of the first known item; only populated when type == BEFORE_FIRST_ITEM.
-        Limits mFirstKnownItem;
-        // Limits of the last known item; only populated when type == AFTER_LAST_ITEM.
-        Limits mLastKnownItem;
-
-        /**
-         * @param limitsList The sorted limits list for the coordinate type. If this
-         *     CoordinateLocation is an x-value, mXLimitsList should be passed; otherwise,
-         *     mYLimitsList should be pased.
-         * @param value The coordinate value.
-         */
-        RelativeCoordinate(List<Limits> limitsList, int value) {
-            int index = Collections.binarySearch(limitsList, new Limits(value, value));
-
-            if (index >= 0) {
-                this.type = WITHIN_LIMITS;
-                this.limitsBeforeCoordinate = limitsList.get(index);
-            } else if (~index == 0) {
-                this.type = BEFORE_FIRST_ITEM;
-                this.mFirstKnownItem = limitsList.get(0);
-            } else if (~index == limitsList.size()) {
-                Limits lastLimits = limitsList.get(limitsList.size() - 1);
-                if (lastLimits.lowerLimit <= value && value <= lastLimits.upperLimit) {
-                    this.type = WITHIN_LIMITS;
-                    this.limitsBeforeCoordinate = lastLimits;
-                } else {
-                    this.type = AFTER_LAST_ITEM;
-                    this.mLastKnownItem = lastLimits;
-                }
-            } else {
-                Limits limitsBeforeIndex = limitsList.get(~index - 1);
-                if (limitsBeforeIndex.lowerLimit <= value
-                        && value <= limitsBeforeIndex.upperLimit) {
-                    this.type = WITHIN_LIMITS;
-                    this.limitsBeforeCoordinate = limitsList.get(~index - 1);
-                } else {
-                    this.type = BETWEEN_TWO_ITEMS;
-                    this.limitsBeforeCoordinate = limitsList.get(~index - 1);
-                    this.limitsAfterCoordinate = limitsList.get(~index);
-                }
-            }
-        }
-
-        int toComparisonValue() {
-            if (type == BEFORE_FIRST_ITEM) {
-                return mFirstKnownItem.lowerLimit - 1;
-            } else if (type == AFTER_LAST_ITEM) {
-                return mLastKnownItem.upperLimit + 1;
-            } else if (type == BETWEEN_TWO_ITEMS) {
-                return limitsBeforeCoordinate.upperLimit + 1;
-            } else {
-                return limitsBeforeCoordinate.lowerLimit;
-            }
-        }
-
-        @Override
-        public int hashCode() {
-            return mFirstKnownItem.lowerLimit
-                    ^ mLastKnownItem.upperLimit
-                    ^ limitsBeforeCoordinate.upperLimit
-                    ^ limitsBeforeCoordinate.lowerLimit;
-        }
-
-        @Override
-        public boolean equals(Object other) {
-            if (!(other instanceof RelativeCoordinate)) {
-                return false;
-            }
-
-            RelativeCoordinate otherCoordinate = (RelativeCoordinate) other;
-            return toComparisonValue() == otherCoordinate.toComparisonValue();
-        }
-
-        @Override
-        public int compareTo(RelativeCoordinate other) {
-            return toComparisonValue() - other.toComparisonValue();
-        }
-    }
-
-    /**
-     * The location of a point relative to the Limits of nearby items; consists of both an x- and
-     * y-RelativeCoordinateLocation.
-     */
-    private class RelativePoint {
-        final RelativeCoordinate xLocation;
-        final RelativeCoordinate yLocation;
-
-        RelativePoint(Point point) {
-            this.xLocation = new RelativeCoordinate(mColumnBounds, point.x);
-            this.yLocation = new RelativeCoordinate(mRowBounds, point.y);
-        }
-
-        @Override
-        public int hashCode() {
-            return xLocation.toComparisonValue()
-                    ^ yLocation.toComparisonValue();
-        }
-
-        @Override
-        public boolean equals(Object other) {
-            if (!(other instanceof RelativePoint)) {
-                return false;
-            }
-
-            RelativePoint otherPoint = (RelativePoint) other;
-            return xLocation.equals(otherPoint.xLocation) && yLocation.equals(otherPoint.yLocation);
-        }
-    }
-
-    /**
-     * Generates a rectangle which contains the items selected by the pointer and origin.
-     * @return The rectangle, or null if no items were selected.
-     */
-    private Rect computeBounds() {
-        Rect rect = new Rect();
-        rect.left = getCoordinateValue(
-                min(mRelativeOrigin.xLocation, mRelativePointer.xLocation),
-                mColumnBounds,
-                true);
-        rect.right = getCoordinateValue(
-                max(mRelativeOrigin.xLocation, mRelativePointer.xLocation),
-                mColumnBounds,
-                false);
-        rect.top = getCoordinateValue(
-                min(mRelativeOrigin.yLocation, mRelativePointer.yLocation),
-                mRowBounds,
-                true);
-        rect.bottom = getCoordinateValue(
-                max(mRelativeOrigin.yLocation, mRelativePointer.yLocation),
-                mRowBounds,
-                false);
-        return rect;
-    }
-
-    /**
-     * Computes the corner of the selection nearest the origin.
-     * @return
-     */
-    private int computeCornerNearestOrigin() {
-        int cornerValue = 0;
-
-        if (mRelativeOrigin.yLocation ==
-                min(mRelativeOrigin.yLocation, mRelativePointer.yLocation)) {
-            cornerValue |= UPPER;
-        } else {
-            cornerValue |= LOWER;
-        }
-
-        if (mRelativeOrigin.xLocation ==
-                min(mRelativeOrigin.xLocation, mRelativePointer.xLocation)) {
-            cornerValue |= LEFT;
-        } else {
-            cornerValue |= RIGHT;
-        }
-
-        return cornerValue;
-    }
-
-    private RelativeCoordinate min(RelativeCoordinate first, RelativeCoordinate second) {
-        return first.compareTo(second) < 0 ? first : second;
-    }
-
-    private RelativeCoordinate max(RelativeCoordinate first, RelativeCoordinate second) {
-        return first.compareTo(second) > 0 ? first : second;
-    }
-
-    /**
-     * @return The absolute coordinate (i.e., the x- or y-value) of the given relative
-     *     coordinate.
-     */
-    private int getCoordinateValue(
-            RelativeCoordinate coordinate, List<Limits> limitsList, boolean isStartOfRange) {
-
-        switch (coordinate.type) {
-            case RelativeCoordinate.BEFORE_FIRST_ITEM:
-                return limitsList.get(0).lowerLimit;
-            case RelativeCoordinate.AFTER_LAST_ITEM:
-                return limitsList.get(limitsList.size() - 1).upperLimit;
-            case RelativeCoordinate.BETWEEN_TWO_ITEMS:
-                if (isStartOfRange) {
-                    return coordinate.limitsAfterCoordinate.lowerLimit;
-                } else {
-                    return coordinate.limitsBeforeCoordinate.upperLimit;
-                }
-            case RelativeCoordinate.WITHIN_LIMITS:
-                return coordinate.limitsBeforeCoordinate.lowerLimit;
-        }
-
-        throw new RuntimeException("Invalid coordinate value.");
-    }
-
-    private boolean areItemsCoveredByBand(
-            RelativePoint first, RelativePoint second) {
-
-        return doesCoordinateLocationCoverItems(first.xLocation, second.xLocation) &&
-                doesCoordinateLocationCoverItems(first.yLocation, second.yLocation);
-    }
-
-    private boolean doesCoordinateLocationCoverItems(
-            RelativeCoordinate pointerCoordinate, RelativeCoordinate originCoordinate) {
-
-        if (pointerCoordinate.type == RelativeCoordinate.BEFORE_FIRST_ITEM &&
-                originCoordinate.type == RelativeCoordinate.BEFORE_FIRST_ITEM) {
-            return false;
-        }
-
-        if (pointerCoordinate.type == RelativeCoordinate.AFTER_LAST_ITEM &&
-                originCoordinate.type == RelativeCoordinate.AFTER_LAST_ITEM) {
-            return false;
-        }
-
-        if (pointerCoordinate.type == RelativeCoordinate.BETWEEN_TWO_ITEMS &&
-                originCoordinate.type == RelativeCoordinate.BETWEEN_TWO_ITEMS &&
-                pointerCoordinate.limitsBeforeCoordinate.equals(
-                        originCoordinate.limitsBeforeCoordinate) &&
-                pointerCoordinate.limitsAfterCoordinate.equals(
-                        originCoordinate.limitsAfterCoordinate)) {
-            return false;
-        }
-
-        return true;
-    }
-}
\ No newline at end of file
diff --git a/src/com/android/documentsui/selection/ItemDetailsLookup.java b/src/com/android/documentsui/selection/ItemDetailsLookup.java
deleted file mode 100644
index 8c0490192..000000000
--- a/src/com/android/documentsui/selection/ItemDetailsLookup.java
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.MotionEvent;
-
-import javax.annotation.Nullable;
-
-/**
- * Provides event handlers w/ access to details about documents details
- * view items Documents in the UI (RecyclerView).
- */
-public abstract class ItemDetailsLookup {
-
-    /** @return true if there is an item under the finger/cursor. */
-    public abstract boolean overItem(MotionEvent e);
-
-    /** @return true if there is an item w/ a stable ID under the finger/cursor. */
-    public abstract boolean overStableItem(MotionEvent e);
-
-    /**
-     * @return true if the event is over an area that can be dragged via touch
-     * or via mouse. List items have a white area that is not draggable.
-     */
-    public abstract boolean inItemDragRegion(MotionEvent e);
-
-    /**
-     * @return true if the event is in the "selection hot spot" region.
-     * The hot spot region instantly selects in touch mode, vs launches.
-     */
-    public abstract boolean inItemSelectRegion(MotionEvent e);
-
-    /**
-     * @return the adapter position of the item under the finger/cursor.
-     */
-    public abstract int getItemPosition(MotionEvent e);
-
-    /**
-     * @return the DocumentDetails for the item under the event, or null.
-     */
-    public abstract @Nullable ItemDetails getItemDetails(MotionEvent e);
-
-    /**
-     * Abstract class providing helper classes with access to information about
-     * RecyclerView item associated with a MotionEvent.
-     */
-    public static abstract class ItemDetails {
-
-        public boolean hasPosition() {
-            return getPosition() > RecyclerView.NO_POSITION;
-        }
-
-        public abstract int getPosition();
-
-        public boolean hasStableId() {
-            return getStableId() != null;
-        }
-
-        public abstract @Nullable String getStableId();
-
-        /**
-         * @return The view type of this ViewHolder.
-         */
-        public abstract int getItemViewType();
-
-        /**
-         * @return true if the event is in an area of the item that should be
-         * directly interpreted as a user wishing to select the item. This
-         * is useful for checkboxes and other UI affordances focused on enabling
-         * selection.
-         */
-        public boolean inSelectionHotspot(MotionEvent e) {
-            return false;
-        }
-
-        /**
-         * Events in the drag region will not be processed as selection events. This
-         * allows the client to implement custom handling for events related to drag
-         * and drop.
-         */
-        public boolean inDragRegion(MotionEvent e) {
-            return false;
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            if (obj instanceof ItemDetails) {
-                return equals((ItemDetails) obj);
-            }
-            return false;
-        }
-
-        private boolean equals(ItemDetails other) {
-            return this.getPosition() == other.getPosition()
-                    && this.getStableId() == other.getStableId();
-        }
-
-        @Override
-        public int hashCode() {
-            return getPosition() >>> 8;
-        }
-    }
-}
diff --git a/src/com/android/documentsui/selection/MotionEvents.java b/src/com/android/documentsui/selection/MotionEvents.java
deleted file mode 100644
index 1915c5ab6..000000000
--- a/src/com/android/documentsui/selection/MotionEvents.java
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import android.graphics.Point;
-import android.view.KeyEvent;
-import android.view.MotionEvent;
-
-/**
- * Utility methods for working with {@link MotionEvent} instances.
- */
-final class MotionEvents {
-
-    private MotionEvents() {}
-
-    static boolean isMouseEvent(MotionEvent e) {
-        return e.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE;
-    }
-
-    static boolean isTouchEvent(MotionEvent e) {
-        return e.getToolType(0) == MotionEvent.TOOL_TYPE_FINGER;
-    }
-
-    static boolean isActionMove(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_MOVE;
-    }
-
-    static boolean isActionDown(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_DOWN;
-    }
-
-    static boolean isActionUp(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_UP;
-    }
-
-    static boolean isActionPointerUp(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_POINTER_UP;
-    }
-
-    static boolean isActionPointerDown(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_POINTER_DOWN;
-    }
-
-    static boolean isActionCancel(MotionEvent e) {
-        return e.getActionMasked() == MotionEvent.ACTION_CANCEL;
-    }
-
-    static Point getOrigin(MotionEvent e) {
-        return new Point((int) e.getX(), (int) e.getY());
-    }
-
-    static boolean isPrimaryButtonPressed(MotionEvent e) {
-        return e.isButtonPressed(MotionEvent.BUTTON_PRIMARY);
-    }
-
-    public static boolean isSecondaryButtonPressed(MotionEvent e) {
-        return e.isButtonPressed(MotionEvent.BUTTON_SECONDARY);
-    }
-
-    public static boolean isTertiaryButtonPressed(MotionEvent e) {
-        return e.isButtonPressed(MotionEvent.BUTTON_TERTIARY);
-    }
-
-    static boolean isShiftKeyPressed(MotionEvent e) {
-        return hasBit(e.getMetaState(), KeyEvent.META_SHIFT_ON);
-    }
-
-    static boolean isCtrlKeyPressed(MotionEvent e) {
-        return hasBit(e.getMetaState(), KeyEvent.META_CTRL_ON);
-    }
-
-    static boolean isAltKeyPressed(MotionEvent e) {
-        return hasBit(e.getMetaState(), KeyEvent.META_ALT_ON);
-    }
-
-    public static boolean isTouchpadScroll(MotionEvent e) {
-        // Touchpad inputs are treated as mouse inputs, and when scrolling, there are no buttons
-        // returned.
-        return isMouseEvent(e) && isActionMove(e) && e.getButtonState() == 0;
-    }
-
-    private static boolean hasBit(int metaState, int bit) {
-        return (metaState & bit) != 0;
-    }
-}
diff --git a/src/com/android/documentsui/selection/MotionInputHandler.java b/src/com/android/documentsui/selection/MotionInputHandler.java
deleted file mode 100644
index f52a637e0..000000000
--- a/src/com/android/documentsui/selection/MotionInputHandler.java
+++ /dev/null
@@ -1,100 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import android.view.GestureDetector.SimpleOnGestureListener;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-
-/**
- * Base class for handlers that can be registered w/ {@link GestureRouter}.
- */
-public abstract class MotionInputHandler extends SimpleOnGestureListener {
-
-    protected final SelectionHelper mSelectionHelper;
-    protected final ItemDetailsLookup mDetailsLookup;
-
-    private final Callbacks mCallbacks;
-
-    public MotionInputHandler(
-            SelectionHelper selectionHelper,
-            ItemDetailsLookup detailsLookup,
-            Callbacks callbacks) {
-
-        checkArgument(selectionHelper != null);
-        checkArgument(detailsLookup != null);
-        checkArgument(callbacks != null);
-
-        mSelectionHelper = selectionHelper;
-        mDetailsLookup = detailsLookup;
-        mCallbacks = callbacks;
-    }
-
-    protected final boolean selectItem(ItemDetails details) {
-        checkArgument(details != null);
-        checkArgument(details.hasPosition());
-        checkArgument(details.hasStableId());
-
-        if (mSelectionHelper.select(details.getStableId())) {
-            mSelectionHelper.anchorRange(details.getPosition());
-        }
-
-        // we set the focus on this doc so it will be the origin for keyboard events or shift+clicks
-        // if there is only a single item selected, otherwise clear focus
-        if (mSelectionHelper.getSelection().size() == 1) {
-            mCallbacks.focusItem(details);
-        } else {
-            mCallbacks.clearFocus();
-        }
-        return true;
-    }
-
-    protected final boolean focusItem(ItemDetails details) {
-        checkArgument(details != null);
-        checkArgument(details.hasStableId());
-
-        mSelectionHelper.clearSelection();
-        mCallbacks.focusItem(details);
-        return true;
-    }
-
-    protected final void extendSelectionRange(ItemDetails details) {
-        checkArgument(details.hasPosition());
-        checkArgument(details.hasStableId());
-
-        mSelectionHelper.extendRange(details.getPosition());
-        mCallbacks.focusItem(details);
-    }
-
-    protected final boolean isRangeExtension(MotionEvent e) {
-        return MotionEvents.isShiftKeyPressed(e) && mSelectionHelper.isRangeActive();
-    }
-
-    protected boolean shouldClearSelection(MotionEvent e, ItemDetails item) {
-        return !MotionEvents.isCtrlKeyPressed(e)
-                && !item.inSelectionHotspot(e)
-                && !mSelectionHelper.isSelected(item.getStableId());
-    }
-
-    public static abstract class Callbacks {
-        public abstract void onPerformHapticFeedback();
-        public void focusItem(ItemDetails item) {}
-        public void clearFocus() {}
-    }
-}
diff --git a/src/com/android/documentsui/selection/MouseInputHandler.java b/src/com/android/documentsui/selection/MouseInputHandler.java
deleted file mode 100644
index 7ceb0f5fa..000000000
--- a/src/com/android/documentsui/selection/MouseInputHandler.java
+++ /dev/null
@@ -1,215 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static com.android.documentsui.selection.Shared.DEBUG;
-import static com.android.documentsui.selection.Shared.VERBOSE;
-
-import android.util.Log;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-import com.android.internal.widget.RecyclerView;
-
-import javax.annotation.Nullable;
-
-/**
- * A MotionInputHandler that provides the high-level glue for mouse/stylus driven selection. This
- * class works with {@link RecyclerView}, {@link GestureRouter}, and {@link GestureSelectionHelper}
- * to provide robust user drive selection support.
- */
-public final class MouseInputHandler extends MotionInputHandler {
-
-        private static final String TAG = "MouseInputDelegate";
-
-        private final Callbacks mCallbacks;
-
-        // The event has been handled in onSingleTapUp
-        private boolean mHandledTapUp;
-        // true when the previous event has consumed a right click motion event
-        private boolean mHandledOnDown;
-
-        public MouseInputHandler(
-                SelectionHelper selectionHelper,
-                ItemDetailsLookup detailsLookup,
-                Callbacks callbacks) {
-
-            super(selectionHelper, detailsLookup, callbacks);
-
-            mCallbacks = callbacks;
-        }
-
-        @Override
-        public boolean onDown(MotionEvent e) {
-            if (VERBOSE) Log.v(TAG, "Delegated onDown event.");
-            if ((MotionEvents.isAltKeyPressed(e) && MotionEvents.isPrimaryButtonPressed(e))
-                    || MotionEvents.isSecondaryButtonPressed(e)) {
-                mHandledOnDown = true;
-                return onRightClick(e);
-            }
-
-            return false;
-        }
-
-        @Override
-        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
-            // Don't scroll content window in response to mouse drag
-            // If it's two-finger trackpad scrolling, we want to scroll
-            return !MotionEvents.isTouchpadScroll(e2);
-        }
-
-        @Override
-        public boolean onSingleTapUp(MotionEvent e) {
-            // See b/27377794. Since we don't get a button state back from UP events, we have to
-            // explicitly save this state to know whether something was previously handled by
-            // DOWN events or not.
-            if (mHandledOnDown) {
-                if (VERBOSE) Log.v(TAG, "Ignoring onSingleTapUp, previously handled in onDown.");
-                mHandledOnDown = false;
-                return false;
-            }
-
-            if (!mDetailsLookup.overStableItem(e)) {
-                if (DEBUG) Log.d(TAG, "Tap not associated w/ model item. Clearing selection.");
-                mSelectionHelper.clearSelection();
-                mCallbacks.clearFocus();
-                return false;
-            }
-
-            if (MotionEvents.isTertiaryButtonPressed(e)) {
-                if (DEBUG) Log.d(TAG, "Ignoring middle click");
-                return false;
-            }
-
-            ItemDetails item = mDetailsLookup.getItemDetails(e);
-            if (mSelectionHelper.hasSelection()) {
-                if (isRangeExtension(e)) {
-                    extendSelectionRange(item);
-                } else {
-                    if (shouldClearSelection(e, item)) {
-                        mSelectionHelper.clearSelection();
-                    }
-                    if (mSelectionHelper.isSelected(item.getStableId())) {
-                        if (mSelectionHelper.deselect(item.getStableId())) {
-                            mCallbacks.clearFocus();
-                        }
-                    } else {
-                        selectOrFocusItem(item, e);
-                    }
-                }
-                mHandledTapUp = true;
-                return true;
-            }
-
-            return false;
-        }
-
-        @Override
-        public boolean onSingleTapConfirmed(MotionEvent e) {
-            if (mHandledTapUp) {
-                if (VERBOSE) Log.v(TAG,
-                        "Ignoring onSingleTapConfirmed, previously handled in onSingleTapUp.");
-                mHandledTapUp = false;
-                return false;
-            }
-
-            if (mSelectionHelper.hasSelection()) {
-                return false;  // should have been handled by onSingleTapUp.
-            }
-
-            if (!mDetailsLookup.overItem(e)) {
-                if (DEBUG) Log.d(TAG, "Ignoring Confirmed Tap on non-item.");
-                return false;
-            }
-
-            if (MotionEvents.isTertiaryButtonPressed(e)) {
-                if (DEBUG) Log.d(TAG, "Ignoring middle click");
-                return false;
-            }
-
-            @Nullable ItemDetails item = mDetailsLookup.getItemDetails(e);
-            if (item == null || !item.hasStableId()) {
-                Log.w(TAG, "Ignoring Confirmed Tap. No document details associated w/ event.");
-                return false;
-            }
-
-            if (mCallbacks.hasFocusedItem() && MotionEvents.isShiftKeyPressed(e)) {
-                mSelectionHelper.startRange(mCallbacks.getFocusedPosition());
-                mSelectionHelper.extendRange(item.getPosition());
-            } else {
-                selectOrFocusItem(item, e);
-            }
-            return true;
-        }
-
-        @Override
-        public boolean onDoubleTap(MotionEvent e) {
-            mHandledTapUp = false;
-
-            if (!mDetailsLookup.overStableItem(e)) {
-                if (DEBUG) Log.d(TAG, "Ignoring DoubleTap on non-model-backed item.");
-                return false;
-            }
-
-            if (MotionEvents.isTertiaryButtonPressed(e)) {
-                if (DEBUG) Log.d(TAG, "Ignoring middle click");
-                return false;
-            }
-
-            @Nullable ItemDetails item = mDetailsLookup.getItemDetails(e);
-            if (item != null) {
-                return mCallbacks.onItemActivated(item, e);
-            }
-
-            return false;
-        }
-
-        private boolean onRightClick(MotionEvent e) {
-            if (mDetailsLookup.overStableItem(e)) {
-                @Nullable ItemDetails item = mDetailsLookup.getItemDetails(e);
-                if (item != null && !mSelectionHelper.isSelected(item.getStableId())) {
-                    mSelectionHelper.clearSelection();
-                    selectItem(item);
-                }
-            }
-
-            // We always delegate final handling of the event,
-            // since the handler might want to show a context menu
-            // in an empty area or some other weirdo view.
-            return mCallbacks.onContextClick(e);
-        }
-
-        private void selectOrFocusItem(ItemDetails item, MotionEvent e) {
-            if (item.inSelectionHotspot(e) || MotionEvents.isCtrlKeyPressed(e)) {
-                selectItem(item);
-            } else {
-                focusItem(item);
-            }
-        }
-
-        public static abstract class Callbacks extends MotionInputHandler.Callbacks {
-            public abstract boolean onItemActivated(ItemDetails item, MotionEvent e);
-            public boolean onContextClick(MotionEvent e) {
-                return false;
-            }
-            public boolean hasFocusedItem() {
-                return false;
-            }
-            public int getFocusedPosition() {
-                return RecyclerView.NO_POSITION;
-            }
-        }
-    }
\ No newline at end of file
diff --git a/src/com/android/documentsui/selection/MutableSelection.java b/src/com/android/documentsui/selection/MutableSelection.java
deleted file mode 100644
index 7939e14ef..000000000
--- a/src/com/android/documentsui/selection/MutableSelection.java
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-/**
- * Subclass of Selection exposing public support for mutating the underlying selection data.
- * This is useful for clients of {@link SelectionHelper} that wish to manipulate
- * a copy of selection data obtained via {@link SelectionHelper#copySelection(Selection)}.
- */
-public final class MutableSelection extends Selection {
-
-    @Override
-    public boolean add(String id) {
-        return super.add(id);
-    }
-
-    @Override
-    public boolean remove(String id) {
-        return super.remove(id);
-    }
-
-    @Override
-    public void clear() {
-        super.clear();
-    }
-}
diff --git a/src/com/android/documentsui/selection/Range.java b/src/com/android/documentsui/selection/Range.java
deleted file mode 100644
index 001e92d28..000000000
--- a/src/com/android/documentsui/selection/Range.java
+++ /dev/null
@@ -1,151 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-import static androidx.recyclerview.widget.RecyclerView.NO_POSITION;
-import static com.android.documentsui.selection.Shared.DEBUG;
-import static com.android.documentsui.selection.Shared.TAG;
-
-import android.util.Log;
-
-import com.android.documentsui.selection.DefaultSelectionHelper.RangeType;
-
-/**
- * Class providing support for managing range selections.
- */
-final class Range {
-
-    private final Callbacks mCallbacks;
-    private final int mBegin;
-    private int mEnd = NO_POSITION;
-
-    public Range(Callbacks callbacks, int begin) {
-        if (DEBUG) Log.d(TAG, "New Ranger created beginning @ " + begin);
-        mCallbacks = callbacks;
-        mBegin = begin;
-    }
-
-    void extendSelection(int position, @RangeType int type) {
-        checkArgument(position != NO_POSITION, "Position cannot be NO_POSITION.");
-
-        if (mEnd == NO_POSITION || mEnd == mBegin) {
-            // Reset mEnd so it can be established in establishRange.
-            mEnd = NO_POSITION;
-            establishRange(position, type);
-        } else {
-            reviseRange(position, type);
-        }
-    }
-
-    private void establishRange(int position, @RangeType int type) {
-        checkArgument(mEnd == NO_POSITION, "End has already been set.");
-
-        if (position == mBegin) {
-            mEnd = position;
-        }
-
-        if (position > mBegin) {
-            updateRange(mBegin + 1, position, true, type);
-        } else if (position < mBegin) {
-            updateRange(position, mBegin - 1, true, type);
-        }
-
-        mEnd = position;
-    }
-
-    private void reviseRange(int position, @RangeType int type) {
-        checkArgument(mEnd != NO_POSITION, "End must already be set.");
-        checkArgument(mBegin != mEnd, "Beging and end point to same position.");
-
-        if (position == mEnd) {
-            if (DEBUG) Log.v(TAG, "Ignoring no-op revision for range: " + this);
-        }
-
-        if (mEnd > mBegin) {
-            reviseAscendingRange(position, type);
-        } else if (mEnd < mBegin) {
-            reviseDescendingRange(position, type);
-        }
-        // the "else" case is covered by checkState at beginning of method.
-
-        mEnd = position;
-    }
-
-    /**
-     * Updates an existing ascending selection.
-     * @param position
-     */
-    private void reviseAscendingRange(int position, @RangeType int type) {
-        // Reducing or reversing the range....
-        if (position < mEnd) {
-            if (position < mBegin) {
-                updateRange(mBegin + 1, mEnd, false, type);
-                updateRange(position, mBegin -1, true, type);
-            } else {
-                updateRange(position + 1, mEnd, false, type);
-            }
-        }
-
-        // Extending the range...
-        else if (position > mEnd) {
-            updateRange(mEnd + 1, position, true, type);
-        }
-    }
-
-    private void reviseDescendingRange(int position, @RangeType int type) {
-        // Reducing or reversing the range....
-        if (position > mEnd) {
-            if (position > mBegin) {
-                updateRange(mEnd, mBegin - 1, false, type);
-                updateRange(mBegin + 1, position, true, type);
-            } else {
-                updateRange(mEnd, position - 1, false, type);
-            }
-        }
-
-        // Extending the range...
-        else if (position < mEnd) {
-            updateRange(position, mEnd - 1, true, type);
-        }
-    }
-
-    /**
-     * Try to set selection state for all elements in range. Not that callbacks can cancel
-     * selection of specific items, so some or even all items may not reflect the desired state
-     * after the update is complete.
-     *
-     * @param begin Adapter position for range start (inclusive).
-     * @param end Adapter position for range end (inclusive).
-     * @param selected New selection state.
-     */
-    private void updateRange(int begin, int end, boolean selected, @RangeType int type) {
-        mCallbacks.updateForRange(begin, end, selected, type);
-    }
-
-    @Override
-    public String toString() {
-        return "Range{begin=" + mBegin + ", end=" + mEnd + "}";
-    }
-
-    /*
-     * @see {@link DefaultSelectionHelper#updateForRange(int, int , boolean, int)}.
-     */
-    static abstract class Callbacks {
-        abstract void updateForRange(
-                int begin, int end, boolean selected, @RangeType int type);
-    }
-}
diff --git a/src/com/android/documentsui/selection/Selection.java b/src/com/android/documentsui/selection/Selection.java
deleted file mode 100644
index d929bd013..000000000
--- a/src/com/android/documentsui/selection/Selection.java
+++ /dev/null
@@ -1,302 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import android.os.Parcel;
-import android.os.Parcelable;
-import androidx.annotation.VisibleForTesting;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.Map;
-import java.util.Set;
-
-import javax.annotation.Nullable;
-
-/**
- * Object representing the current selection and provisional selection. Provides read only public
- * access, and private write access.
- * <p>
- * This class tracks selected items by managing two sets:
- *
- * <li>primary selection
- *
- * Primary selection consists of items tapped by a user or by lassoed by band select operation.
- *
- * <li>provisional selection
- *
- * Provisional selections are selections which have been temporarily created
- * by an in-progress band select or gesture selection. Once the user releases the mouse button
- * or lifts their finger the corresponding provisional selection should be converted into
- * primary selection.
- *
- * <p>The total selection is the combination of
- * both the core selection and the provisional selection. Tracking both separately is necessary to
- * ensure that items in the core selection are not "erased" from the core selection when they
- * are temporarily included in a secondary selection (like band selection).
- */
-public class Selection implements Iterable<String>, Parcelable {
-
-    final Set<String> mSelection;
-    final Set<String> mProvisionalSelection;
-
-    public Selection() {
-        mSelection = new HashSet<>();
-        mProvisionalSelection = new HashSet<>();
-    }
-
-    /**
-     * Used by CREATOR.
-     */
-    private Selection(Set<String> selection) {
-        mSelection = selection;
-        mProvisionalSelection = new HashSet<>();
-    }
-
-    /**
-     * @param id
-     * @return true if the position is currently selected.
-     */
-    public boolean contains(@Nullable String id) {
-        return mSelection.contains(id) || mProvisionalSelection.contains(id);
-    }
-
-    /**
-     * Returns an {@link Iterator} that iterators over the selection, *excluding*
-     * any provisional selection.
-     *
-     * {@inheritDoc}
-     */
-    @Override
-    public Iterator<String> iterator() {
-        return mSelection.iterator();
-    }
-
-    /**
-     * @return size of the selection including both final and provisional selected items.
-     */
-    public int size() {
-        return mSelection.size() + mProvisionalSelection.size();
-    }
-
-    /**
-     * @return true if the selection is empty.
-     */
-    public boolean isEmpty() {
-        return mSelection.isEmpty() && mProvisionalSelection.isEmpty();
-    }
-
-    /**
-     * Sets the provisional selection, which is a temporary selection that can be saved,
-     * canceled, or adjusted at a later time. When a new provision selection is applied, the old
-     * one (if it exists) is abandoned.
-     * @return Map of ids added or removed. Added ids have a value of true, removed are false.
-     */
-    Map<String, Boolean> setProvisionalSelection(Set<String> newSelection) {
-        Map<String, Boolean> delta = new HashMap<>();
-
-        for (String id: mProvisionalSelection) {
-            // Mark each item that used to be in the provisional selection
-            // but is not in the new provisional selection.
-            if (!newSelection.contains(id) && !mSelection.contains(id)) {
-                delta.put(id, false);
-            }
-        }
-
-        for (String id: mSelection) {
-            // Mark each item that used to be in the selection but is unsaved and not in the new
-            // provisional selection.
-            if (!newSelection.contains(id)) {
-                delta.put(id, false);
-            }
-        }
-
-        for (String id: newSelection) {
-            // Mark each item that was not previously in the selection but is in the new
-            // provisional selection.
-            if (!mSelection.contains(id) && !mProvisionalSelection.contains(id)) {
-                delta.put(id, true);
-            }
-        }
-
-        // Now, iterate through the changes and actually add/remove them to/from the current
-        // selection. This could not be done in the previous loops because changing the size of
-        // the selection mid-iteration changes iteration order erroneously.
-        for (Map.Entry<String, Boolean> entry: delta.entrySet()) {
-            String id = entry.getKey();
-            if (entry.getValue()) {
-                mProvisionalSelection.add(id);
-            } else {
-                mProvisionalSelection.remove(id);
-            }
-        }
-
-        return delta;
-    }
-
-    /**
-     * Saves the existing provisional selection. Once the provisional selection is saved,
-     * subsequent provisional selections which are different from this existing one cannot
-     * cause items in this existing provisional selection to become deselected.
-     */
-    @VisibleForTesting
-    protected void mergeProvisionalSelection() {
-        mSelection.addAll(mProvisionalSelection);
-        mProvisionalSelection.clear();
-    }
-
-    /**
-     * Abandons the existing provisional selection so that all items provisionally selected are
-     * now deselected.
-     */
-    @VisibleForTesting
-    void clearProvisionalSelection() {
-        mProvisionalSelection.clear();
-    }
-
-    /**
-     * Adds a new item to the primary selection.
-     *
-     * @return true if the operation resulted in a modification to the selection.
-     */
-    boolean add(String id) {
-        if (mSelection.contains(id)) {
-            return false;
-        }
-
-        mSelection.add(id);
-        return true;
-    }
-
-    /**
-     * Removes an item from the primary selection.
-     *
-     * @return true if the operation resulted in a modification to the selection.
-     */
-    boolean remove(String id) {
-        if (!mSelection.contains(id)) {
-            return false;
-        }
-
-        mSelection.remove(id);
-        return true;
-    }
-
-    /**
-     * Clears the primary selection. The provisional selection, if any, is unaffected.
-     */
-    void clear() {
-        mSelection.clear();
-    }
-
-    /**
-     * Trims this selection to be the intersection of itself and {@code ids}.
-     */
-    void intersect(Collection<String> ids) {
-        checkArgument(ids != null);
-
-        mSelection.retainAll(ids);
-        mProvisionalSelection.retainAll(ids);
-    }
-
-    /**
-     * Clones primary and provisional selection from supplied {@link Selection}.
-     * Does not copy active range data.
-     */
-    @VisibleForTesting
-    void copyFrom(Selection source) {
-        mSelection.clear();
-        mSelection.addAll(source.mSelection);
-
-        mProvisionalSelection.clear();
-        mProvisionalSelection.addAll(source.mProvisionalSelection);
-    }
-
-    @Override
-    public String toString() {
-        if (size() <= 0) {
-            return "size=0, items=[]";
-        }
-
-        StringBuilder buffer = new StringBuilder(size() * 28);
-        buffer.append("Selection{")
-            .append("primary{size=" + mSelection.size())
-            .append(", entries=" + mSelection)
-            .append("}, provisional{size=" + mProvisionalSelection.size())
-            .append(", entries=" + mProvisionalSelection)
-            .append("}}");
-        return buffer.toString();
-    }
-
-    @Override
-    public int hashCode() {
-        return mSelection.hashCode() ^ mProvisionalSelection.hashCode();
-    }
-
-    @Override
-    public boolean equals(Object other) {
-        if (this == other) {
-            return true;
-        }
-
-        return other instanceof Selection
-            ? equals((Selection) other)
-            : false;
-    }
-
-    private boolean equals(Selection other) {
-        return mSelection.equals(((Selection) other).mSelection) &&
-                mProvisionalSelection.equals(((Selection) other).mProvisionalSelection);
-    }
-
-    @Override
-    public int describeContents() {
-        return 0;
-    }
-
-    @Override
-    public void writeToParcel(Parcel dest, int flags) {
-        dest.writeStringList(new ArrayList<>(mSelection));
-        // We don't include provisional selection since it is
-        // typically coupled to some other runtime state (like a band).
-    }
-
-    public static final ClassLoaderCreator<Selection> CREATOR =
-            new ClassLoaderCreator<Selection>() {
-        @Override
-        public Selection createFromParcel(Parcel in) {
-            return createFromParcel(in, null);
-        }
-
-        @Override
-        public Selection createFromParcel(Parcel in, ClassLoader loader) {
-            ArrayList<String> selected = new ArrayList<>();
-            in.readStringList(selected);
-
-            return new Selection(new HashSet<>(selected));
-        }
-
-        @Override
-        public Selection[] newArray(int size) {
-            return new Selection[size];
-        }
-    };
-}
\ No newline at end of file
diff --git a/src/com/android/documentsui/selection/SelectionHelper.java b/src/com/android/documentsui/selection/SelectionHelper.java
deleted file mode 100644
index bd8b34eaa..000000000
--- a/src/com/android/documentsui/selection/SelectionHelper.java
+++ /dev/null
@@ -1,237 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import java.util.List;
-import java.util.Set;
-
-/**
- * SelectionManager provides support for managing selection within a RecyclerView instance.
- *
- * @see DefaultSelectionHelper for details on instantiation.
- */
-public abstract class SelectionHelper {
-
-    /**
-     * This value is included in the payload when SelectionHelper implementations
-     * notify RecyclerView of changes. Clients can look for this in
-     * {@code onBindViewHolder} to know if the bind event is occurring in response
-     * to a selection state change.
-     */
-    public static final String SELECTION_CHANGED_MARKER = "Selection-Changed";
-
-    /**
-     * Adds {@code observe} to be notified when changes to selection occur.
-     *
-     * @param observer
-     */
-    public abstract void addObserver(SelectionObserver observer);
-
-    public abstract boolean hasSelection();
-
-    /**
-     * Returns a Selection object that provides a live view on the current selection.
-     *
-     * @see #copySelection(Selection) on how to get a snapshot
-     *     of the selection that will not reflect future changes
-     *     to selection.
-     *
-     * @return The current selection.
-     */
-    public abstract Selection getSelection();
-
-    /**
-     * Updates {@code dest} to reflect the current selection.
-     * @param dest
-     */
-    public abstract void copySelection(Selection dest);
-
-    /**
-     * @return true if the item specified by its id is selected. Shorthand for
-     * {@code getSelection().contains(String)}.
-     */
-    public abstract boolean isSelected(String id);
-
-    /**
-     * Restores the selected state of specified items. Used in cases such as restore the selection
-     * after rotation etc. Provisional selection, being provisional 'n all, isn't restored.
-     */
-    public abstract void restoreSelection(Selection other);
-
-    /**
-     * Sets the selected state of the specified items. Note that the callback will NOT
-     * be consulted to see if an item can be selected.
-     *
-     * @param ids
-     * @param selected
-     * @return
-     */
-    public abstract boolean setItemsSelected(Iterable<String> ids, boolean selected);
-
-    /**
-     * Clears the selection and notifies (if something changes).
-     */
-    public abstract void clearSelection();
-
-    /**
-     * Attempts to select an item.
-     *
-     * @return true if the item was selected. False if the item was not selected, or was
-     *         was already selected prior to the method being called.
-     */
-    public abstract boolean select(String itemId);
-
-    /**
-     * Attempts to deselect an item.
-     *
-     * @return true if the item was deselected. False if the item was not deselected, or was
-     *         was already deselected prior to the method being called.
-     */
-    public abstract boolean deselect(String itemId);
-
-    /**
-     * Starts a range selection. If a range selection is already active, this will start a new range
-     * selection (which will reset the range anchor).
-     *
-     * @param pos The anchor position for the selection range.
-     */
-    public abstract void startRange(int pos);
-
-    /**
-     * Sets the end point for the active range selection.
-     *
-     * <p>This function should only be called when a range selection is active
-     * (see {@link #isRangeActive()}. Items in the range [anchor, end] will be
-     * selected.
-     *
-     * @param pos The new end position for the selection range.
-     * @param type The type of selection the range should utilize.
-     *
-     * @throws IllegalStateException if a range selection is not active. Range selection
-     *         must have been started by a call to {@link #startRange(int)}.
-     */
-    public abstract void extendRange(int pos);
-
-    /**
-     * Stops an in-progress range selection. All selection done with
-     * {@link #extendProvisionalRange(int)} will be lost if
-     * {@link Selection#mergeProvisionalSelection()} is not called beforehand.
-     */
-    public abstract void endRange();
-
-    /**
-     * @return Whether or not there is a current range selection active.
-     */
-    public abstract boolean isRangeActive();
-
-    /**
-     * Sets the magic location at which a selection range begins (the selection anchor). This value
-     * is consulted when determining how to extend, and modify selection ranges. Calling this when a
-     * range selection is active will reset the range selection.
-     */
-    public abstract void anchorRange(int position);
-
-    /**
-     * @param pos
-     */
-    // TODO: This is smelly. Maybe this type of logic needs to move into range selection,
-    // then selection manager can have a startProvisionalRange and startRange. Or
-    // maybe ranges always start life as provisional.
-    public abstract void extendProvisionalRange(int pos);
-
-    /**
-     * @param newSelection
-     */
-    public abstract void setProvisionalSelection(Set<String> newSelection);
-
-    /**
-     *
-     */
-    public abstract void clearProvisionalSelection();
-
-    public abstract void mergeProvisionalSelection();
-
-    /**
-     * Observer interface providing access to information about Selection state changes.
-     */
-    public static abstract class SelectionObserver {
-
-        /**
-         * Called when state of an item has been changed.
-         */
-        public void onItemStateChanged(String id, boolean selected) {}
-
-        /**
-         * Called when the underlying data set has change. After this method is called
-         * the selection manager will attempt traverse the existing selection,
-         * calling {@link #onItemStateChanged(String, boolean)} for each selected item,
-         * and deselecting any items that cannot be selected given the updated dataset.
-         */
-        public void onSelectionReset() {}
-
-        /**
-         * Called immediately after completion of any set of changes, excluding
-         * those resulting in calls to {@link #onSelectionReset()} and
-         * {@link #onSelectionRestored()}.
-         */
-        public void onSelectionChanged() {}
-
-        /**
-         * Called immediately after selection is restored.
-         * {@link #onItemStateChanged(String, boolean)} will not be called
-         * for individual items in the selection.
-         */
-        public void onSelectionRestored() {}
-    }
-
-    /**
-     * Facilitates the use of stable ids.
-     */
-    public static abstract class StableIdProvider {
-        /**
-         * @return The model ID of the item at the given adapter position.
-         */
-        public abstract String getStableId(int position);
-
-        /**
-         * @return the position of a stable ID, or RecyclerView.NO_POSITION.
-         */
-        public abstract int getPosition(String id);
-
-        /**
-         * @return A list of all known stable IDs.
-         */
-        public abstract List<String> getStableIds();
-    }
-
-    /**
-     * Implement SelectionPredicate to control when items can be selected or unselected.
-     */
-    public static abstract class SelectionPredicate {
-
-        /** @return true if the item at {@code id} can be set to {@code nextState}. */
-        public abstract boolean canSetStateForId(String id, boolean nextState);
-
-        /** @return true if the item at {@code id} can be set to {@code nextState}. */
-        public abstract boolean canSetStateAtPosition(int position, boolean nextState);
-
-        /** @return true if more than a single item can be selected. */
-        public boolean canSelectMultiple() {
-            return true;
-        }
-    }
-}
diff --git a/src/com/android/documentsui/selection/Shared.java b/src/com/android/documentsui/selection/Shared.java
deleted file mode 100644
index bf30919dc..000000000
--- a/src/com/android/documentsui/selection/Shared.java
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-/**
- * Shared constants used in this and descendant packages.
- */
-public final class Shared {
-
-    public static final String TAG = "SelectionHelper";
-    public static final boolean DEBUG = false;
-    public static final boolean VERBOSE = false;
-
-    private Shared() {}
-}
diff --git a/src/com/android/documentsui/selection/ToolHandlerRegistry.java b/src/com/android/documentsui/selection/ToolHandlerRegistry.java
deleted file mode 100644
index 4a6aa16a1..000000000
--- a/src/com/android/documentsui/selection/ToolHandlerRegistry.java
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-import static androidx.core.util.Preconditions.checkState;
-
-import androidx.annotation.Nullable;
-import android.view.MotionEvent;
-
-import java.util.Arrays;
-import java.util.List;
-
-/**
- * Registry for tool specific event handler.
- */
-final class ToolHandlerRegistry<T> {
-
-    // Currently there are four known input types. ERASER is the last one, so has the
-    // highest value. UNKNOWN is zero, so we add one. This allows delegates to be
-    // registered by type, and avoid the auto-boxing that would be necessary were we
-    // to store delegates in a Map<Integer, Delegate>.
-    private static final int sNumInputTypes = MotionEvent.TOOL_TYPE_ERASER + 1;
-
-    private final List<T> mHandlers = Arrays.asList(null, null, null, null, null);
-    private final T mDefault;
-
-    ToolHandlerRegistry(T defaultDelegate) {
-        checkArgument(defaultDelegate != null);
-        mDefault = defaultDelegate;
-
-        // Initialize all values to null.
-        for (int i = 0; i < sNumInputTypes; i++) {
-            mHandlers.set(i, null);
-        }
-    }
-
-    /**
-     * @param toolType
-     * @param delegate the delegate, or null to unregister.
-     * @throws IllegalStateException if an tooltype handler is already registered.
-     */
-    void set(int toolType, @Nullable T delegate) {
-        checkArgument(toolType >= 0 && toolType <= MotionEvent.TOOL_TYPE_ERASER);
-        checkState(mHandlers.get(toolType) == null);
-
-        mHandlers.set(toolType, delegate);
-    }
-
-    T get(MotionEvent e) {
-        T d = mHandlers.get(e.getToolType(0));
-        return d != null ? d : mDefault;
-    }
-}
diff --git a/src/com/android/documentsui/selection/TouchEventRouter.java b/src/com/android/documentsui/selection/TouchEventRouter.java
deleted file mode 100644
index 232b56067..000000000
--- a/src/com/android/documentsui/selection/TouchEventRouter.java
+++ /dev/null
@@ -1,102 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener;
-import android.view.GestureDetector;
-import android.view.MotionEvent;
-
-/**
- * A class responsible for routing MotionEvents to tool-type specific handlers,
- * and if not handled by a handler, on to a {@link GestureDetector} for further
- * processing.
- *
- * <p>TouchEventRouter takes its name from
- * {@link RecyclerView#addOnItemTouchListener(OnItemTouchListener)}. Despite "Touch"
- * being in the name, it receives MotionEvents for all types of tools.
- */
-public final class TouchEventRouter implements OnItemTouchListener {
-
-    private final GestureDetector mDetector;
-    private final ToolHandlerRegistry<OnItemTouchListener> mDelegates;
-
-    public TouchEventRouter(GestureDetector detector, OnItemTouchListener defaultDelegate) {
-        checkArgument(detector != null);
-        checkArgument(defaultDelegate != null);
-
-        mDetector = detector;
-        mDelegates = new ToolHandlerRegistry<>(defaultDelegate);
-    }
-
-    public TouchEventRouter(GestureDetector detector) {
-        this(
-                detector,
-                // Default listener does nothing.
-                new OnItemTouchListener() {
-                    @Override
-                    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
-                        return false;
-                    }
-
-                    @Override
-                    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
-                    }
-
-                    @Override
-                    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
-                    }
-                });
-    }
-
-    /**
-     * @param toolType See MotionEvent for details on available types.
-     * @param delegate An {@link OnItemTouchListener} to receive events
-     *     of {@code toolType}.
-     */
-    public void register(int toolType, OnItemTouchListener delegate) {
-        checkArgument(delegate != null);
-        mDelegates.set(toolType, delegate);
-    }
-
-    @Override
-    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
-        boolean handled = mDelegates.get(e).onInterceptTouchEvent(rv, e);
-
-        // Forward all events to UserInputHandler.
-        // This is necessary since UserInputHandler needs to always see the first DOWN event. Or
-        // else all future UP events will be tossed.
-        handled |= mDetector.onTouchEvent(e);
-
-        return handled;
-    }
-
-    @Override
-    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
-        mDelegates.get(e).onTouchEvent(rv, e);
-
-        // Note: even though this event is being handled as part of gestures such as drag and band,
-        // continue forwarding to the GestureDetector. The detector needs to see the entire cluster
-        // of events in order to properly interpret other gestures, such as long press.
-        mDetector.onTouchEvent(e);
-    }
-
-    @Override
-    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {}
-}
diff --git a/src/com/android/documentsui/selection/TouchInputHandler.java b/src/com/android/documentsui/selection/TouchInputHandler.java
deleted file mode 100644
index ffb6bce8d..000000000
--- a/src/com/android/documentsui/selection/TouchInputHandler.java
+++ /dev/null
@@ -1,147 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection;
-
-import static com.android.documentsui.base.SharedMinimal.DEBUG;
-
-import androidx.recyclerview.widget.RecyclerView;
-import android.util.Log;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-
-/**
- * A MotionInputHandler that provides the high-level glue for touch driven selection. This class
- * works with {@link RecyclerView}, {@link GestureRouter}, and {@link GestureSelectionHelper} to
- * provide robust user drive selection support.
- */
-public final class TouchInputHandler extends MotionInputHandler {
-    private static final String TAG = "TouchInputDelegate";
-
-    private final SelectionPredicate mSelectionPredicate;
-    private final Callbacks mCallbacks;
-    private final Runnable mGestureKicker;
-
-    public TouchInputHandler(
-            SelectionHelper selectionHelper,
-            ItemDetailsLookup detailsLookup,
-            SelectionPredicate selectionPredicate,
-            Runnable gestureKicker,
-            Callbacks callbacks) {
-
-        super(selectionHelper, detailsLookup, callbacks);
-
-        mSelectionPredicate = selectionPredicate;
-        mGestureKicker = gestureKicker;
-        mCallbacks = callbacks;
-    }
-
-    public TouchInputHandler(
-            SelectionHelper selectionHelper,
-            ItemDetailsLookup detailsLookup,
-            SelectionPredicate selectionPredicate,
-            GestureSelectionHelper gestureHelper,
-            Callbacks callbacks) {
-
-        this(
-                selectionHelper,
-                detailsLookup,
-                selectionPredicate,
-                new Runnable() {
-                    @Override
-                    public void run() {
-                        gestureHelper.start();
-                    }
-                },
-                callbacks);
-    }
-
-    @Override
-    public boolean onSingleTapUp(MotionEvent e) {
-        if (!mDetailsLookup.overStableItem(e)) {
-            if (DEBUG) Log.d(TAG, "Tap not associated w/ model item. Clearing selection.");
-            mSelectionHelper.clearSelection();
-            return false;
-        }
-
-        ItemDetails item = mDetailsLookup.getItemDetails(e);
-        if (mSelectionHelper.hasSelection()) {
-            if (isRangeExtension(e)) {
-                extendSelectionRange(item);
-            } else if (mSelectionHelper.isSelected(item.getStableId())) {
-                mSelectionHelper.deselect(item.getStableId());
-            } else {
-                selectItem(item);
-            }
-
-            return true;
-        }
-
-        // Touch events select if they occur in the selection hotspot,
-        // otherwise they activate.
-        return item.inSelectionHotspot(e)
-                ? selectItem(item)
-                : mCallbacks.onItemActivated(item, e);
-    }
-
-    @Override
-    public final void onLongPress(MotionEvent e) {
-        if (!mDetailsLookup.overStableItem(e)) {
-            if (DEBUG) Log.d(TAG, "Ignoring LongPress on non-model-backed item.");
-            return;
-        }
-
-        ItemDetails item = mDetailsLookup.getItemDetails(e);
-        boolean handled = false;
-
-        if (isRangeExtension(e)) {
-            extendSelectionRange(item);
-            handled = true;
-        } else {
-            if (!mSelectionHelper.isSelected(item.getStableId())
-                    && mSelectionPredicate.canSetStateForId(item.getStableId(), true)) {
-                // If we cannot select it, we didn't apply anchoring - therefore should not
-                // start gesture selection
-                if (selectItem(item)) {
-                    // And finally if the item was selected && we can select multiple
-                    // we kick off gesture selection.
-                    if (mSelectionPredicate.canSelectMultiple()) {
-                        mGestureKicker.run();
-                    }
-                    handled = true;
-                }
-            } else {
-                // We only initiate drag and drop on long press for touch to allow regular
-                // touch-based scrolling
-                // mTouchDragListener.accept(e);
-                mCallbacks.onDragInitiated(e);
-                handled = true;
-            }
-        }
-
-        if (handled) {
-            mCallbacks.onPerformHapticFeedback();
-        }
-    }
-
-    public static abstract class Callbacks extends MotionInputHandler.Callbacks {
-        public abstract boolean onItemActivated(ItemDetails item, MotionEvent e);
-        public boolean onDragInitiated(MotionEvent e) {
-            return false;
-        }
-    }
-}
diff --git a/src/com/android/documentsui/selection/demo/DemoDetailsLookup.java b/src/com/android/documentsui/selection/demo/DemoDetailsLookup.java
deleted file mode 100644
index c49014e8a..000000000
--- a/src/com/android/documentsui/selection/demo/DemoDetailsLookup.java
+++ /dev/null
@@ -1,81 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.demo;
-
-import androidx.annotation.Nullable;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.ViewHolder;
-import android.view.MotionEvent;
-import android.view.View;
-
-import com.android.documentsui.selection.ItemDetailsLookup;
-
-/**
- * Access to details of an item associated with a {@link MotionEvent} instance.
- */
-final class DemoDetailsLookup extends ItemDetailsLookup {
-
-    private final RecyclerView mRecView;
-
-    public DemoDetailsLookup(RecyclerView view) {
-        mRecView = view;
-    }
-
-    @Override
-    public boolean overItem(MotionEvent e) {
-        return getItemPosition(e) != RecyclerView.NO_POSITION;
-    }
-
-    @Override
-    public boolean overStableItem(MotionEvent e) {
-        return overItem(e) && getItemDetails(e).hasStableId();
-    }
-
-    @Override
-    public boolean inItemDragRegion(MotionEvent e) {
-        return overItem(e) && getItemDetails(e).inDragRegion(e);
-    }
-
-    @Override
-    public boolean inItemSelectRegion(MotionEvent e) {
-        return overItem(e) && getItemDetails(e).inSelectionHotspot(e);
-    }
-
-    @Override
-    public int getItemPosition(MotionEvent e) {
-        View child = mRecView.findChildViewUnder(e.getX(), e.getY());
-        return (child != null)
-                ? mRecView.getChildAdapterPosition(child)
-                : RecyclerView.NO_POSITION;
-    }
-
-    @Override
-    public ItemDetails getItemDetails(MotionEvent e) {
-        @Nullable DemoHolder holder = getDemoHolder(e);
-        return holder == null ? null : holder.getItemDetails();
-    }
-
-    private @Nullable DemoHolder getDemoHolder(MotionEvent e) {
-        View childView = mRecView.findChildViewUnder(e.getX(), e.getY());
-        if (childView != null) {
-            ViewHolder holder = mRecView.getChildViewHolder(childView);
-            if (holder instanceof DemoHolder) {
-                return (DemoHolder) holder;
-            }
-        }
-        return null;
-    }
-}
diff --git a/src/com/android/documentsui/selection/demo/DemoHolder.java b/src/com/android/documentsui/selection/demo/DemoHolder.java
deleted file mode 100644
index ade72c7dd..000000000
--- a/src/com/android/documentsui/selection/demo/DemoHolder.java
+++ /dev/null
@@ -1,118 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.demo;
-
-import android.graphics.Rect;
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.MotionEvent;
-import android.widget.LinearLayout;
-import android.widget.TextView;
-
-import com.android.documentsui.R;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-
-public final class DemoHolder extends RecyclerView.ViewHolder {
-
-        private final LinearLayout mContainer;
-        public final TextView mSelector;
-        public final TextView mLabel;
-        private final Details mDetails;
-        private DemoItem mItem;
-
-        DemoHolder(LinearLayout layout) {
-            super(layout);
-            mContainer = layout.findViewById(R.id.container);
-            mSelector = layout.findViewById(R.id.selector);
-            mLabel = layout.findViewById(R.id.label);
-            mDetails = new Details(this);
-        }
-
-        public void update(DemoItem demoItem) {
-            mItem = demoItem;
-            mLabel.setText(mItem.getName());
-        }
-
-        void setSelected(boolean selected) {
-            mContainer.setActivated(selected);
-            mSelector.setActivated(selected);
-        }
-
-        public String getStableId() {
-            return mItem != null ? mItem.getId() : null;
-        }
-
-        public boolean inDragRegion(MotionEvent e) {
-            // If itemView is activated = selected, then whole region is interactive
-            if (mContainer.isActivated()) {
-                return true;
-            }
-
-            if (inSelectRegion(e)) {
-                return true;
-            }
-
-            Rect rect = new Rect();
-            mLabel.getPaint().getTextBounds(
-                    mLabel.getText().toString(), 0, mLabel.getText().length(), rect);
-
-            // If the tap occurred inside the text, these are interactive spots.
-            return rect.contains((int) e.getRawX(), (int) e.getRawY());
-        }
-
-        public boolean inSelectRegion(MotionEvent e) {
-            Rect iconRect = new Rect();
-            mSelector.getGlobalVisibleRect(iconRect);
-            return iconRect.contains((int) e.getRawX(), (int) e.getRawY());
-        }
-
-        Details getItemDetails() {
-            return mDetails;
-        }
-
-        private static final class Details extends ItemDetails {
-
-            private final DemoHolder mHolder;
-
-            Details(DemoHolder holder) {
-                mHolder = holder;
-            }
-
-            @Override
-            public int getPosition() {
-                return mHolder.getAdapterPosition();
-            }
-
-            @Override
-            public String getStableId() {
-                return mHolder.getStableId();
-            }
-
-            @Override
-            public int getItemViewType() {
-                return mHolder.getItemViewType();
-            }
-
-            @Override
-            public boolean inDragRegion(MotionEvent e) {
-                return mHolder.inDragRegion(e);
-            }
-
-            @Override
-            public boolean inSelectionHotspot(MotionEvent e) {
-                return mHolder.inSelectRegion(e);
-            }
-        }
-    }
\ No newline at end of file
diff --git a/src/com/android/documentsui/selection/demo/DemoItem.java b/src/com/android/documentsui/selection/demo/DemoItem.java
deleted file mode 100644
index 15755a0e9..000000000
--- a/src/com/android/documentsui/selection/demo/DemoItem.java
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.demo;
-
-public class DemoItem {
-
-    private final String mId;
-    private final String mName;
-
-    DemoItem(String id, String name) {
-        mId = id;
-        mName = name;
-    }
-
-    public String getId() {
-        return mId;
-    }
-
-    public String getName() {
-        return mName;
-    }
-}
diff --git a/src/com/android/documentsui/selection/demo/DemoStableIdProvider.java b/src/com/android/documentsui/selection/demo/DemoStableIdProvider.java
deleted file mode 100644
index 5b5332ec8..000000000
--- a/src/com/android/documentsui/selection/demo/DemoStableIdProvider.java
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.demo;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import com.android.documentsui.selection.SelectionHelper.StableIdProvider;
-
-import java.util.List;
-
-/**
- * Provides RecyclerView selection code access to stable ids backed
- * by DocumentsAdapter.
- */
-final class DemoStableIdProvider extends StableIdProvider {
-
-    private final SelectionDemoAdapter mAdapter;
-
-    public DemoStableIdProvider(SelectionDemoAdapter adapter) {
-        checkArgument(adapter != null);
-        mAdapter = adapter;
-    }
-
-    @Override
-    public String getStableId(int position) {
-        return mAdapter.getStableId(position);
-    }
-
-    @Override
-    public int getPosition(String id) {
-        return mAdapter.getPosition(id);
-    }
-
-    @Override
-    public List<String> getStableIds() {
-        return mAdapter.getStableIds();
-    }
-}
diff --git a/src/com/android/documentsui/selection/demo/SelectionDemoActivity.java b/src/com/android/documentsui/selection/demo/SelectionDemoActivity.java
deleted file mode 100644
index 90857745c..000000000
--- a/src/com/android/documentsui/selection/demo/SelectionDemoActivity.java
+++ /dev/null
@@ -1,360 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection.demo;
-
-import android.content.Context;
-import android.os.Bundle;
-import androidx.annotation.CallSuper;
-import androidx.appcompat.app.AppCompatActivity;
-import androidx.recyclerview.widget.GridLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.appcompat.widget.Toolbar;
-import android.view.GestureDetector;
-import android.view.HapticFeedbackConstants;
-import android.view.Menu;
-import android.view.MenuItem;
-import android.view.MotionEvent;
-import android.widget.Toast;
-
-import com.android.documentsui.R;
-import com.android.documentsui.selection.BandSelectionHelper;
-import com.android.documentsui.selection.ContentLock;
-import com.android.documentsui.selection.DefaultBandHost;
-import com.android.documentsui.selection.DefaultBandPredicate;
-import com.android.documentsui.selection.DefaultSelectionHelper;
-import com.android.documentsui.selection.GestureRouter;
-import com.android.documentsui.selection.GestureSelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-import com.android.documentsui.selection.MotionInputHandler;
-import com.android.documentsui.selection.MouseInputHandler;
-import com.android.documentsui.selection.MutableSelection;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-import com.android.documentsui.selection.SelectionHelper.StableIdProvider;
-import com.android.documentsui.selection.TouchEventRouter;
-import com.android.documentsui.selection.TouchInputHandler;
-import com.android.documentsui.selection.demo.SelectionDemoAdapter.OnBindCallback;
-
-/**
- * ContentPager demo activity.
- */
-public class SelectionDemoActivity extends AppCompatActivity {
-
-    private static final String EXTRA_SAVED_SELECTION = "demo-saved-selection";
-    private static final String EXTRA_COLUMN_COUNT = "demo-column-count";
-
-    private Toolbar mToolbar;
-    private SelectionDemoAdapter mAdapter;
-    private SelectionHelper mSelectionHelper;
-
-    private RecyclerView mRecView;
-    private GridLayoutManager mLayout;
-    private int mColumnCount = 1;  // This will get updated when layout changes.
-
-    @Override
-    protected void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        setContentView(R.layout.selection_demo_layout);
-        mToolbar = findViewById(R.id.toolbar);
-        setSupportActionBar(mToolbar);
-        mRecView = (RecyclerView) findViewById(R.id.list);
-
-        mLayout = new GridLayoutManager(this, mColumnCount);
-        mRecView.setLayoutManager(mLayout);
-
-        mAdapter = new SelectionDemoAdapter(this);
-        mRecView.setAdapter(mAdapter);
-
-        StableIdProvider stableIds = new DemoStableIdProvider(mAdapter);
-
-        // SelectionPredicate permits client control of which items can be selected.
-        SelectionPredicate canSelectAnything = new SelectionPredicate() {
-            @Override
-            public boolean canSetStateForId(String id, boolean nextState) {
-                return true;
-            }
-
-            @Override
-            public boolean canSetStateAtPosition(int position, boolean nextState) {
-                return true;
-            }
-        };
-
-        // TODO: Reload content when it changes. Could use CursorLoader.
-        // TODO: Retain selection. Restore when content changes.
-
-        mSelectionHelper = new DefaultSelectionHelper(
-                DefaultSelectionHelper.MODE_MULTIPLE,
-                mAdapter,
-                stableIds,
-                canSelectAnything);
-
-        // onBind event callback that allows items to be updated to reflect
-        // selection status when bound by recycler view.
-        // This allows us to defer initialization of the SelectionHelper dependency
-        // which itself depends on the Adapter.
-        mAdapter.addOnBindCallback(
-                new OnBindCallback() {
-                    @Override
-                    void onBound(DemoHolder holder, int position) {
-                        String id = mAdapter.getStableId(position);
-                        holder.setSelected(mSelectionHelper.isSelected(id));
-                    }
-                });
-
-        ItemDetailsLookup detailsLookup = new DemoDetailsLookup(mRecView);
-
-        // Setup basic input handling, with the touch handler as the default consumer
-        // of events. If mouse handling is configured as well, the mouse input
-        // related handlers will intercept mouse input events.
-
-        // GestureRouter is responsible for routing GestureDetector events
-        // to tool-type specific handlers.
-        GestureRouter<MotionInputHandler> gestureRouter = new GestureRouter<>();
-        GestureDetector gestureDetector = new GestureDetector(this, gestureRouter);
-
-        // TouchEventRouter takes its name from RecyclerView#OnItemTouchListener.
-        // Despite "Touch" being in the name, it receives events for all types of tools.
-        // This class is responsible for routing events to tool-type specific handlers,
-        // and if not handled by a handler, on to a GestureDetector for analysis.
-        TouchEventRouter eventRouter = new TouchEventRouter(gestureDetector);
-
-        // Content lock provides a mechanism to block content reload while selection
-        // activities are active. If using a loader to load content, route
-        // the call through the content lock using ContentLock#runWhenUnlocked.
-        // This is especially useful when listening on content change notification.
-        ContentLock contentLock = new ContentLock();
-
-        // GestureSelectionHelper provides logic that interprets a combination
-        // of motions and gestures in order to provide gesture driven selection support
-        // when used in conjunction with RecyclerView.
-        GestureSelectionHelper gestureHelper = GestureSelectionHelper.create(
-                mSelectionHelper, mRecView, contentLock, detailsLookup);
-
-        // Finally hook the framework up to listening to recycle view events.
-        mRecView.addOnItemTouchListener(eventRouter);
-
-        // But before you move on, there's more work to do. Event plumbing has been
-        // installed, but we haven't registered any of our helpers or callbacks.
-        // Helpers contain predefined logic converting events into selection related events.
-        // Callbacks provide authors the ability to reponspond to other types of
-        // events (like "active" a tapped item). This is broken up into two main
-        // suites, one for "touch" and one for "mouse", though both can and should (usually)
-        // be configued to handle other types of input (to satisfy user expectation).
-
-        // TOUCH (+ UNKNOWN) handeling provides gesture based selection allowing
-        // the user to long press on an item, then drag her finger over other
-        // items in order to extend the selection.
-        TouchCallbacks touchCallbacks = new TouchCallbacks(this, mRecView);
-
-        // Provides high level glue for binding touch events and gestures to selection framework.
-        TouchInputHandler touchHandler = new TouchInputHandler(
-                mSelectionHelper, detailsLookup, canSelectAnything, gestureHelper, touchCallbacks);
-
-        eventRouter.register(MotionEvent.TOOL_TYPE_FINGER, gestureHelper);
-        eventRouter.register(MotionEvent.TOOL_TYPE_UNKNOWN, gestureHelper);
-
-        gestureRouter.register(MotionEvent.TOOL_TYPE_FINGER, touchHandler);
-        gestureRouter.register(MotionEvent.TOOL_TYPE_UNKNOWN, touchHandler);
-
-        // MOUSE (+ STYLUS) handeling provides band based selection allowing
-        // the user to click down in an empty area, then drag her mouse
-        // to create a band that covers the items she wants selected.
-        //
-        // PRO TIP: Don't skip installing mouse/stylus support. It provides
-        // improved productivity and demonstrates feature maturity that users
-        // will appreciate. See InputManager for details on more sophisticated
-        // strategies on detecting the presence of input tools.
-
-        // Provides high level glue for binding mouse/stylus events and gestures
-        // to selection framework.
-        MouseInputHandler mouseHandler = new MouseInputHandler(
-                mSelectionHelper, detailsLookup, new MouseCallbacks(this, mRecView));
-
-        DefaultBandHost host = new DefaultBandHost(
-                mRecView, R.drawable.selection_demo_band_overlay);
-
-        // BandSelectionHelper provides support for band selection on-top of a RecyclerView
-        // instance. Given the recycling nature of RecyclerView BandSelectionController
-        // necessarily models and caches list/grid information as the user's pointer
-        // interacts with the item in the RecyclerView. Selectable items that intersect
-        // with the band, both on and off screen, are selected.
-        BandSelectionHelper bandHelper = new BandSelectionHelper(
-                host,
-                mAdapter,
-                stableIds,
-                mSelectionHelper,
-                canSelectAnything,
-                new DefaultBandPredicate(detailsLookup),
-                contentLock);
-
-
-        eventRouter.register(MotionEvent.TOOL_TYPE_MOUSE, bandHelper);
-        eventRouter.register(MotionEvent.TOOL_TYPE_STYLUS, bandHelper);
-
-        gestureRouter.register(MotionEvent.TOOL_TYPE_MOUSE, mouseHandler);
-        gestureRouter.register(MotionEvent.TOOL_TYPE_STYLUS, mouseHandler);
-
-        // Aaaaan, all done with mouse/stylus selection setup!
-
-        updateFromSavedState(savedInstanceState);
-    }
-
-    @Override
-    protected void onSaveInstanceState(Bundle state) {
-        super.onSaveInstanceState(state);
-        MutableSelection selection = new MutableSelection();
-        mSelectionHelper.copySelection(selection);
-        state.putParcelable(EXTRA_SAVED_SELECTION, selection);
-        state.putInt(EXTRA_COLUMN_COUNT, mColumnCount);
-    }
-
-    private void updateFromSavedState(Bundle state) {
-        // In order to preserve selection across various lifecycle events be sure to save
-        // the selection in onSaveInstanceState, and to restore it when present in the Bundle
-        // pass in via onCreate(Bundle).
-        if (state != null) {
-            if (state.containsKey(EXTRA_SAVED_SELECTION)) {
-                Selection savedSelection = state.getParcelable(EXTRA_SAVED_SELECTION);
-                if (!savedSelection.isEmpty()) {
-                    mSelectionHelper.restoreSelection(savedSelection);
-                    CharSequence text = "Selection restored.";
-                    Toast.makeText(this, "Selection restored.", Toast.LENGTH_SHORT).show();
-                }
-            }
-            if (state.containsKey(EXTRA_COLUMN_COUNT)) {
-                mColumnCount = state.getInt(EXTRA_COLUMN_COUNT);
-                mLayout.setSpanCount(mColumnCount);
-            }
-        }
-    }
-
-    @Override
-    public boolean onCreateOptionsMenu(Menu menu) {
-        boolean showMenu = super.onCreateOptionsMenu(menu);
-        getMenuInflater().inflate(R.menu.selection_demo_actions, menu);
-        return showMenu;
-    }
-
-    @Override
-    @CallSuper
-    public boolean onPrepareOptionsMenu(Menu menu) {
-        super.onPrepareOptionsMenu(menu);
-        menu.findItem(R.id.option_menu_add_column).setEnabled(mColumnCount <= 3);
-        menu.findItem(R.id.option_menu_remove_column).setEnabled(mColumnCount > 1);
-        return true;
-    }
-
-    @Override
-    public boolean onOptionsItemSelected(MenuItem item) {
-        switch (item.getItemId()) {
-            case R.id.option_menu_add_column:
-                // TODO: Add columns
-                mLayout.setSpanCount(++mColumnCount);
-                return true;
-
-            case R.id.option_menu_remove_column:
-                mLayout.setSpanCount(--mColumnCount);
-                return true;
-            default:
-                return super.onOptionsItemSelected(item);
-        }
-    }
-
-
-    @Override
-    public void onBackPressed () {
-        if (mSelectionHelper.hasSelection()) {
-            mSelectionHelper.clearSelection();
-            mSelectionHelper.clearProvisionalSelection();
-        } else {
-            super.onBackPressed();
-        }
-    }
-
-    private static void toast(Context context, String msg) {
-        Toast.makeText(context, msg, Toast.LENGTH_SHORT).show();
-    }
-
-    @Override
-    protected void onDestroy() {
-        mSelectionHelper.clearSelection();
-        super.onDestroy();
-    }
-
-    @Override
-    protected void onStart() {
-        super.onStart();
-        mAdapter.loadData();
-    }
-
-    // Implementation of MouseInputHandler.Callbacks allows handling
-    // of higher level events, like onActivated.
-    private static final class MouseCallbacks extends MouseInputHandler.Callbacks {
-
-        private final Context mContext;
-        private final RecyclerView mRecView;
-
-        MouseCallbacks(Context context, RecyclerView recView) {
-            mContext = context;
-            mRecView = recView;
-        }
-
-        @Override
-        public boolean onItemActivated(ItemDetails item, MotionEvent e) {
-            toast(mContext, "Activate item: " + item.getStableId());
-            return true;
-        }
-
-        @Override
-        public boolean onContextClick(MotionEvent e) {
-            toast(mContext, "Context click received.");
-            return true;
-        }
-
-        @Override
-        public void onPerformHapticFeedback() {
-            mRecView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
-        }
-    };
-
-    private static final class TouchCallbacks extends TouchInputHandler.Callbacks {
-
-        private final Context mContext;
-        private final RecyclerView mRecView;
-
-        private TouchCallbacks(Context context, RecyclerView recView) {
-
-            mContext = context;
-            mRecView = recView;
-        }
-
-        @Override
-        public boolean onItemActivated(ItemDetails item, MotionEvent e) {
-            toast(mContext, "Activate item: " + item.getStableId());
-            return true;
-        }
-
-        @Override
-        public void onPerformHapticFeedback() {
-            mRecView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/com/android/documentsui/selection/demo/SelectionDemoAdapter.java b/src/com/android/documentsui/selection/demo/SelectionDemoAdapter.java
deleted file mode 100644
index e70b335c5..000000000
--- a/src/com/android/documentsui/selection/demo/SelectionDemoAdapter.java
+++ /dev/null
@@ -1,108 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.demo;
-
-import android.content.Context;
-import androidx.annotation.Nullable;
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.LinearLayout;
-
-import com.android.documentsui.R;
-
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
-final class SelectionDemoAdapter extends RecyclerView.Adapter<DemoHolder> {
-
-    private static final Map<String, DemoItem> sDemoData = new HashMap<>();
-    static {
-        for (int i = 0; i < 1000; i++) {
-            String id = createId(i);
-            sDemoData.put(id, new DemoItem(id, "item" + i));
-        }
-    }
-
-    private final Context mContext;
-    private @Nullable OnBindCallback mBindCallback;
-
-    SelectionDemoAdapter(Context context) {
-        mContext = context;
-    }
-
-    void addOnBindCallback(OnBindCallback bindCallback) {
-        mBindCallback = bindCallback;
-    }
-
-    void loadData() {
-        onDataReady();
-    }
-
-    private void onDataReady() {
-        notifyDataSetChanged();
-    }
-
-    @Override
-    public int getItemCount() {
-        return sDemoData.size();
-    }
-
-    @Override
-    public void onBindViewHolder(DemoHolder holder, int position) {
-        String id = createId(position);
-        holder.update(sDemoData.get(id));
-        if (mBindCallback != null) {
-            mBindCallback.onBound(holder, position);
-        }
-    }
-
-    private static String createId(int position) {
-        return "id" + position;
-    }
-
-    @Override
-    public DemoHolder onCreateViewHolder(ViewGroup parent, int viewType) {
-        LinearLayout layout = inflateLayout(mContext, parent, R.layout.selection_demo_list_item);
-        return new DemoHolder(layout);
-    }
-
-    String getStableId(int position) {
-        return createId(position);
-    }
-
-    int getPosition(String id) {
-        return Integer.parseInt(id.substring(2));
-    }
-
-    List<String> getStableIds() {
-        return new ArrayList<>(sDemoData.keySet());
-    }
-
-    @SuppressWarnings("TypeParameterUnusedInFormals")  // Convenience to avoid clumsy cast.
-    private static <V extends View> V inflateLayout(
-            Context context, ViewGroup parent, int layout) {
-
-        return (V) LayoutInflater.from(context).inflate(layout, parent, false);
-    }
-
-    static abstract class OnBindCallback {
-        abstract void onBound(DemoHolder holder, int position);
-    }
-}
diff --git a/tests/common/com/android/documentsui/SelectionHelpers.java b/tests/common/com/android/documentsui/SelectionHelpers.java
new file mode 100644
index 000000000..2018252cb
--- /dev/null
+++ b/tests/common/com/android/documentsui/SelectionHelpers.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.documentsui;
+
+import androidx.recyclerview.selection.DefaultSelectionTracker;
+import androidx.recyclerview.selection.SelectionPredicates;
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.selection.SelectionTracker.SelectionPredicate;
+import androidx.recyclerview.selection.StorageStrategy;
+
+import com.android.documentsui.testing.TestStableIdProvider;
+
+import java.util.Collections;
+import java.util.List;
+
+public class SelectionHelpers {
+
+    public static final SelectionPredicate<String> CAN_SET_ANYTHING =
+            SelectionPredicates.createSelectAnything();
+
+    private SelectionHelpers() {}
+
+    public static DocsSelectionHelper createTestInstance() {
+        return createTestInstance(Collections.emptyList());
+    }
+
+    public static DocsSelectionHelper createTestInstance(List<String> docs) {
+        DocsSelectionHelper manager = new DocsSelectionHelper(
+                new DocsSelectionHelper.DelegateFactory() {
+
+                    @Override
+                    SelectionTracker<String> create(SelectionTracker<String> selectionTracker) {
+                        return new DefaultSelectionTracker<String>(
+                                Integer.toHexString(System.identityHashCode(docs)),
+                                new TestStableIdProvider(docs),
+                                CAN_SET_ANYTHING,
+                                StorageStrategy.createStringStorage());
+                    }
+                });
+
+        manager.reset(null);
+        return manager;
+    }
+}
diff --git a/tests/common/com/android/documentsui/dirlist/TestDocumentsAdapter.java b/tests/common/com/android/documentsui/dirlist/TestDocumentsAdapter.java
index 2427dc0ca..c7ccaf99f 100644
--- a/tests/common/com/android/documentsui/dirlist/TestDocumentsAdapter.java
+++ b/tests/common/com/android/documentsui/dirlist/TestDocumentsAdapter.java
@@ -18,13 +18,13 @@ package com.android.documentsui.dirlist;
 
 import static org.junit.Assert.assertTrue;
 
+import androidx.recyclerview.selection.SelectionTracker;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.RecyclerView.AdapterDataObserver;
 import android.view.ViewGroup;
 
 import com.android.documentsui.Model.Update;
 import com.android.documentsui.base.EventListener;
-import com.android.documentsui.selection.SelectionHelper;
 import com.android.documentsui.testing.TestEventListener;
 
 import java.util.ArrayList;
@@ -51,7 +51,7 @@ public class TestDocumentsAdapter extends DocumentsAdapter {
 
             @Override
             public void onItemRangeChanged(int startPosition, int itemCount, Object payload) {
-                if (SelectionHelper.SELECTION_CHANGED_MARKER.equals(payload)) {
+                if (SelectionTracker.SELECTION_CHANGED_MARKER.equals(payload)) {
                     int last = startPosition + itemCount;
                     for (int i = startPosition; i < last; i++) {
                         mSelectionChanged.add(i);
diff --git a/tests/common/com/android/documentsui/dirlist/TestFocusHandler.java b/tests/common/com/android/documentsui/dirlist/TestFocusHandler.java
index 8dfbdeaa5..565665566 100644
--- a/tests/common/com/android/documentsui/dirlist/TestFocusHandler.java
+++ b/tests/common/com/android/documentsui/dirlist/TestFocusHandler.java
@@ -59,7 +59,7 @@ public final class TestFocusHandler implements FocusHandler {
     }
 
     @Override
-    public int getFocusPosition() {
+    public int getFocusedPosition() {
         return focusPos;
     }
 
diff --git a/tests/common/com/android/documentsui/testing/SelectionHelpers.java b/tests/common/com/android/documentsui/testing/SelectionHelpers.java
deleted file mode 100644
index 70bc44d91..000000000
--- a/tests/common/com/android/documentsui/testing/SelectionHelpers.java
+++ /dev/null
@@ -1,69 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.testing;
-
-import com.android.documentsui.DocsSelectionHelper;
-import com.android.documentsui.dirlist.DocsStableIdProvider;
-import com.android.documentsui.dirlist.DocumentsAdapter;
-import com.android.documentsui.dirlist.TestDocumentsAdapter;
-import com.android.documentsui.selection.DefaultSelectionHelper;
-import com.android.documentsui.selection.DefaultSelectionHelper.SelectionMode;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-
-import java.util.Collections;
-import java.util.List;
-
-public class SelectionHelpers {
-
-    public static final SelectionPredicate CAN_SET_ANYTHING = new SelectionPredicate() {
-        @Override
-        public boolean canSetStateForId(String id, boolean nextState) {
-            return true;
-        }
-
-        @Override
-        public boolean canSetStateAtPosition(int position, boolean nextState) {
-            return true;
-        }
-    };
-
-    private SelectionHelpers() {}
-
-    public static DocsSelectionHelper createTestInstance() {
-        return createTestInstance(Collections.emptyList());
-    }
-
-    public static DocsSelectionHelper createTestInstance(List<String> docs) {
-        return createTestInstance(docs, DefaultSelectionHelper.MODE_MULTIPLE);
-    }
-
-    public static DocsSelectionHelper createTestInstance(
-            List<String> docs, @SelectionMode int mode) {
-        return createTestInstance(new TestDocumentsAdapter(docs), mode, CAN_SET_ANYTHING);
-    }
-
-    public static DocsSelectionHelper createTestInstance(
-            DocumentsAdapter adapter, @SelectionMode int mode, SelectionPredicate canSetState) {
-        DocsSelectionHelper manager = mode == DefaultSelectionHelper.MODE_SINGLE
-                ? DocsSelectionHelper.createSingleSelect()
-                : DocsSelectionHelper.createMultiSelect();
-
-        manager.reset(adapter, new DocsStableIdProvider(adapter), canSetState);
-
-        return manager;
-    }
-}
diff --git a/tests/common/com/android/documentsui/testing/TestActionHandler.java b/tests/common/com/android/documentsui/testing/TestActionHandler.java
index cd3fb1acf..7b11d41f4 100644
--- a/tests/common/com/android/documentsui/testing/TestActionHandler.java
+++ b/tests/common/com/android/documentsui/testing/TestActionHandler.java
@@ -18,11 +18,12 @@ package com.android.documentsui.testing;
 
 import android.content.Intent;
 
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+
 import com.android.documentsui.AbstractActionHandler;
 import com.android.documentsui.TestActivity;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.RootInfo;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 
 import java.util.function.Consumer;
 
@@ -30,7 +31,7 @@ public class TestActionHandler extends AbstractActionHandler<TestActivity> {
 
     private final TestEnv mEnv;
 
-    public final TestEventHandler<ItemDetails> open = new TestEventHandler<>();
+    public final TestEventHandler<ItemDetails<String>> open = new TestEventHandler<>();
     public boolean mDeleteHappened;
 
     public DocumentInfo nextRootDocument;
@@ -53,7 +54,7 @@ public class TestActionHandler extends AbstractActionHandler<TestActivity> {
     }
 
     @Override
-    public boolean openItem(ItemDetails doc, @ViewType int type, @ViewType int fallback) {
+    public boolean openItem(ItemDetails<String> doc, @ViewType int type, @ViewType int fallback) {
         return open.accept(doc);
     }
 
diff --git a/tests/common/com/android/documentsui/testing/TestDocumentClipper.java b/tests/common/com/android/documentsui/testing/TestDocumentClipper.java
index 3d6c9ad38..9fa4f2e55 100644
--- a/tests/common/com/android/documentsui/testing/TestDocumentClipper.java
+++ b/tests/common/com/android/documentsui/testing/TestDocumentClipper.java
@@ -20,10 +20,11 @@ import android.content.ClipData;
 import android.net.Uri;
 import android.util.Pair;
 
+import androidx.recyclerview.selection.Selection;
+
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.DocumentStack;
 import com.android.documentsui.clipping.DocumentClipper;
-import com.android.documentsui.selection.Selection;
 import com.android.documentsui.services.FileOperationService;
 import com.android.documentsui.services.FileOperationService.OpType;
 import com.android.documentsui.services.FileOperations.Callback;
@@ -49,8 +50,8 @@ public class TestDocumentClipper implements DocumentClipper {
     }
 
     @Override
-    public ClipData getClipDataForDocuments(Function<String, Uri> uriBuilder, Selection selection,
-            int opType) {
+    public ClipData getClipDataForDocuments(
+            Function<String, Uri> uriBuilder, Selection<String> selection, int opType) {
         return nextClip;
     }
 
@@ -67,11 +68,11 @@ public class TestDocumentClipper implements DocumentClipper {
     }
 
     @Override
-    public void clipDocumentsForCopy(Function<String, Uri> uriBuilder, Selection selection) {
+    public void clipDocumentsForCopy(Function<String, Uri> uriBuilder, Selection<String> selection) {
     }
 
     @Override
-    public void clipDocumentsForCut(Function<String, Uri> uriBuilder, Selection selection,
+    public void clipDocumentsForCut(Function<String, Uri> uriBuilder, Selection<String> selection,
             DocumentInfo parent) {
         List<Uri> uris = new ArrayList<>(selection.size());
         for (String id : selection) {
diff --git a/tests/common/com/android/documentsui/testing/TestEnv.java b/tests/common/com/android/documentsui/testing/TestEnv.java
index 40b5e0aee..93cc032a1 100644
--- a/tests/common/com/android/documentsui/testing/TestEnv.java
+++ b/tests/common/com/android/documentsui/testing/TestEnv.java
@@ -23,6 +23,7 @@ import android.test.mock.MockContentResolver;
 import com.android.documentsui.DocsSelectionHelper;
 import com.android.documentsui.FocusManager;
 import com.android.documentsui.Injector;
+import com.android.documentsui.SelectionHelpers;
 import com.android.documentsui.archives.ArchivesProvider;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.Features;
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestSelectionPredicate.java b/tests/common/com/android/documentsui/testing/TestStableIdProvider.java
index 578be3db3..b1acc25dd 100644
--- a/tests/unit/com/android/documentsui/selection/testing/TestSelectionPredicate.java
+++ b/tests/common/com/android/documentsui/testing/TestStableIdProvider.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The Android Open Source Project
+ * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,24 +13,28 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.android.documentsui.selection.testing;
 
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
+package com.android.documentsui.testing;
 
-public final class TestSelectionPredicate extends SelectionPredicate {
-    private boolean mValue;
+import com.android.documentsui.DocsSelectionHelper.StableIdProvider;
 
-    public void setReturnValue(boolean value) {
-        mValue = value;
+import java.util.List;
+
+public class TestStableIdProvider extends StableIdProvider {
+
+    private final List<String> mDocs;
+
+    public TestStableIdProvider(List<String> docs) {
+        mDocs = docs;
     }
 
     @Override
-    public boolean canSetStateForId(String id, boolean nextState) {
-        return mValue;
+    public String getKey(int position) {
+        return mDocs.get(position);
     }
 
     @Override
-    public boolean canSetStateAtPosition(int position, boolean nextState) {
-        return mValue;
+    public int getPosition(String id) {
+        return mDocs.indexOf(id);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/unit/com/android/documentsui/AbstractActionHandlerTest.java b/tests/unit/com/android/documentsui/AbstractActionHandlerTest.java
index d9c551725..cc267bcc0 100644
--- a/tests/unit/com/android/documentsui/AbstractActionHandlerTest.java
+++ b/tests/unit/com/android/documentsui/AbstractActionHandlerTest.java
@@ -28,11 +28,12 @@ import android.provider.DocumentsContract.Path;
 import android.support.test.filters.MediumTest;
 import android.support.test.runner.AndroidJUnit4;
 
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+
 import com.android.documentsui.base.DocumentStack;
 import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.base.Shared;
 import com.android.documentsui.files.LauncherActivity;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 import com.android.documentsui.sorting.SortDimension;
 import com.android.documentsui.sorting.SortModel;
 import com.android.documentsui.testing.DocumentStackAsserts;
@@ -77,7 +78,8 @@ public class AbstractActionHandlerTest {
             }
 
             @Override
-            public boolean openItem(ItemDetails doc, @ViewType int type, @ViewType int fallback) {
+            public boolean openItem(
+                    ItemDetails<String> doc, @ViewType int type, @ViewType int fallback) {
                 throw new UnsupportedOperationException();
             }
 
diff --git a/tests/unit/com/android/documentsui/DocsSelectionHelperTest.java b/tests/unit/com/android/documentsui/DocsSelectionHelperTest.java
index f30464788..de536f581 100644
--- a/tests/unit/com/android/documentsui/DocsSelectionHelperTest.java
+++ b/tests/unit/com/android/documentsui/DocsSelectionHelperTest.java
@@ -23,14 +23,11 @@ import static org.junit.Assert.assertTrue;
 
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
-import androidx.recyclerview.widget.RecyclerView.Adapter;
+
+import androidx.recyclerview.selection.Selection;
+import androidx.recyclerview.selection.SelectionTracker;
 
 import com.android.documentsui.DocsSelectionHelper.DelegateFactory;
-import com.android.documentsui.selection.DefaultSelectionHelper;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-import com.android.documentsui.selection.SelectionHelper.StableIdProvider;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -40,7 +37,6 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 /**
  * Tests for the specialized behaviors provided by DocsSelectionManager.
@@ -57,20 +53,16 @@ public class DocsSelectionHelperTest {
     public void setup() {
         mCreated = new ArrayList<>();
         mFactory = new DelegateFactory() {
-            @Override
-            TestSelectionManager create(
-                    int mode,
-                    Adapter<?> adapter,
-                    StableIdProvider stableIds,
-                    SelectionPredicate canSetState) {
 
+            @Override
+            TestSelectionManager create(SelectionTracker<String> selectionTracker) {
                 TestSelectionManager mgr = new TestSelectionManager();
                 mCreated.add(mgr);
                 return mgr;
             }
         };
 
-        mSelectionMgr = new DocsSelectionHelper(mFactory, DefaultSelectionHelper.MODE_MULTIPLE);
+        mSelectionMgr = new DocsSelectionHelper(mFactory);
     }
 
     @Test
@@ -82,16 +74,16 @@ public class DocsSelectionHelperTest {
 
     @Test
     public void testReset_CreatesNewInstances() {
-        mSelectionMgr.reset(null, null, null);  // nulls are passed to factory. We ignore.
-        mSelectionMgr.reset(null, null, null);  // nulls are passed to factory. We ignore.
+        resetSelectionHelper();
+        resetSelectionHelper();
 
         assertCreated(2);
     }
 
     @Test
     public void testReset_ClearsPreviousSelection() {
-        mSelectionMgr.reset(null, null, null);  // nulls are passed to factory. We ignore.
-        mSelectionMgr.reset(null, null, null);  // nulls are passed to factory. We ignore.
+        resetSelectionHelper();
+        resetSelectionHelper();
 
         mCreated.get(0).assertCleared(true);
         mCreated.get(1).assertCleared(false);
@@ -99,7 +91,7 @@ public class DocsSelectionHelperTest {
 
     @Test
     public void testReplaceSelection() {
-        mSelectionMgr.reset(null, null, null);  // nulls are passed to factory. We ignore.
+        resetSelectionHelper();
 
         List<String> ids = new ArrayList<>();
         ids.add("poodles");
@@ -113,7 +105,11 @@ public class DocsSelectionHelperTest {
         assertEquals(count, mCreated.size());
     }
 
-    private static final class TestSelectionManager extends SelectionHelper {
+    private void resetSelectionHelper() {
+        mSelectionMgr.reset(null); // nulls are passed to factory. We ignore.
+    }
+
+    private static final class TestSelectionManager extends DummySelectionTracker<String> {
 
         private boolean mCleared;
         private Map<String, Boolean> mSelected = new HashMap<>();
@@ -141,12 +137,7 @@ public class DocsSelectionHelperTest {
         }
 
         @Override
-        public Selection getSelection() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void copySelection(Selection dest) {
+        public Selection<String> getSelection() {
             throw new UnsupportedOperationException();
         }
 
@@ -156,7 +147,7 @@ public class DocsSelectionHelperTest {
         }
 
         @Override
-        public void restoreSelection(Selection other) {
+        public void restoreSelection(Selection<String> other) {
             throw new UnsupportedOperationException();
         }
 
@@ -169,8 +160,9 @@ public class DocsSelectionHelperTest {
         }
 
         @Override
-        public void clearSelection() {
+        public boolean clearSelection() {
             mCleared = true;
+            return true;
         }
 
         @Override
@@ -182,50 +174,5 @@ public class DocsSelectionHelperTest {
         public boolean deselect(String itemId) {
             throw new UnsupportedOperationException();
         }
-
-        @Override
-        public void startRange(int pos) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void extendRange(int pos) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void endRange() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public boolean isRangeActive() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void anchorRange(int position) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void extendProvisionalRange(int pos) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void clearProvisionalSelection() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void mergeProvisionalSelection() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void setProvisionalSelection(Set<String> newSelection) {
-            throw new UnsupportedOperationException();
-        }
     }
 }
diff --git a/tests/unit/com/android/documentsui/DragScrollListenerTest.java b/tests/unit/com/android/documentsui/DragScrollListenerTest.java
index dd7db92d1..029228bfa 100644
--- a/tests/unit/com/android/documentsui/DragScrollListenerTest.java
+++ b/tests/unit/com/android/documentsui/DragScrollListenerTest.java
@@ -23,7 +23,7 @@ import android.support.test.runner.AndroidJUnit4;
 import android.view.DragEvent;
 import android.view.View;
 
-import com.android.documentsui.selection.ViewAutoScroller.ScrollerCallbacks;
+import com.android.documentsui.ViewAutoScroller.ScrollerCallbacks;
 import com.android.documentsui.testing.DragEvents;
 import com.android.documentsui.testing.Views;
 
diff --git a/tests/unit/com/android/documentsui/FocusManagerTest.java b/tests/unit/com/android/documentsui/FocusManagerTest.java
index 16301b729..15f703d54 100644
--- a/tests/unit/com/android/documentsui/FocusManagerTest.java
+++ b/tests/unit/com/android/documentsui/FocusManagerTest.java
@@ -16,17 +16,16 @@
 
 package com.android.documentsui;
 
-import androidx.recyclerview.widget.RecyclerView;
 import android.test.AndroidTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
-import com.android.documentsui.base.Features;
+import androidx.recyclerview.selection.SelectionTracker;
+import androidx.recyclerview.widget.RecyclerView;
+
 import com.android.documentsui.dirlist.TestData;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.testing.TestModel;
-import com.android.documentsui.testing.SelectionHelpers;
 import com.android.documentsui.testing.TestFeatures;
 import com.android.documentsui.testing.TestGridLayoutManager;
+import com.android.documentsui.testing.TestModel;
 import com.android.documentsui.testing.TestRecyclerView;
 import com.android.documentsui.testing.Views;
 
@@ -43,7 +42,7 @@ public class FocusManagerTest extends AndroidTestCase {
     private FocusManager mManager;
     private TestRecyclerView mView;
     private TestGridLayoutManager mTestGridLayoutManager;
-    private SelectionHelper mSelectionMgr;
+    private SelectionTracker<String> mSelectionMgr;
     private TestFeatures mFeatures;
 
     @Override
diff --git a/tests/unit/com/android/documentsui/SharedInputHandlerTest.java b/tests/unit/com/android/documentsui/SharedInputHandlerTest.java
index e66c5c05f..4b6151969 100644
--- a/tests/unit/com/android/documentsui/SharedInputHandlerTest.java
+++ b/tests/unit/com/android/documentsui/SharedInputHandlerTest.java
@@ -25,10 +25,10 @@ import android.support.test.runner.AndroidJUnit4;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 
+import androidx.recyclerview.selection.SelectionTracker;
+
 import com.android.documentsui.base.Procedure;
 import com.android.documentsui.dirlist.TestFocusHandler;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.testing.SelectionHelpers;
 import com.android.documentsui.testing.TestDrawerController;
 import com.android.documentsui.testing.TestFeatures;
 
@@ -41,7 +41,7 @@ import org.junit.runner.RunWith;
 public class SharedInputHandlerTest {
 
     private SharedInputHandler mSharedInputHandler;
-    private SelectionHelper mSelectionMgr = SelectionHelpers.createTestInstance();
+    private SelectionTracker<String> mSelectionMgr = SelectionHelpers.createTestInstance();
     private TestFeatures mFeatures = new TestFeatures();
     private TestFocusHandler mFocusHandler = new TestFocusHandler();
     private TestDrawerController mDrawer = TestDrawerController.create();
diff --git a/tests/unit/com/android/documentsui/selection/ViewAutoScrollerTest.java b/tests/unit/com/android/documentsui/ViewAutoScrollerTest.java
index b75c3daab..b3426d30d 100644
--- a/tests/unit/com/android/documentsui/selection/ViewAutoScrollerTest.java
+++ b/tests/unit/com/android/documentsui/ViewAutoScrollerTest.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.android.documentsui.selection;
+package com.android.documentsui;
 
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -23,8 +23,9 @@ import android.graphics.Point;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
 
-import com.android.documentsui.selection.ViewAutoScroller.ScrollHost;
-import com.android.documentsui.selection.ViewAutoScroller.ScrollerCallbacks;
+import com.android.documentsui.ViewAutoScroller;
+import com.android.documentsui.ViewAutoScroller.ScrollHost;
+import com.android.documentsui.ViewAutoScroller.ScrollerCallbacks;
 
 import org.junit.Before;
 import org.junit.Test;
diff --git a/tests/unit/com/android/documentsui/dirlist/DocumentHolderTest.java b/tests/unit/com/android/documentsui/dirlist/DocumentHolderTest.java
index f2187e478..d201a54af 100644
--- a/tests/unit/com/android/documentsui/dirlist/DocumentHolderTest.java
+++ b/tests/unit/com/android/documentsui/dirlist/DocumentHolderTest.java
@@ -30,7 +30,6 @@ import android.view.MotionEvent.PointerCoords;
 import android.view.MotionEvent.PointerProperties;
 
 import com.android.documentsui.R;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
 
 @SmallTest
 public class DocumentHolderTest extends AndroidTestCase {
@@ -99,9 +98,9 @@ public class DocumentHolderTest extends AndroidTestCase {
                 );
     }
 
-    private class TestListener extends KeyboardEventListener {
+    private class TestListener extends KeyboardEventListener<DocumentItemDetails> {
         @Override
-        public boolean onKey(ItemDetails item, int keyCode, KeyEvent event) {
+        public boolean onKey(DocumentItemDetails item, int keyCode, KeyEvent event) {
             return false;
         }
 
diff --git a/tests/unit/com/android/documentsui/dirlist/DragHostTest.java b/tests/unit/com/android/documentsui/dirlist/DragHostTest.java
index 7db69dca3..bb760ad25 100644
--- a/tests/unit/com/android/documentsui/dirlist/DragHostTest.java
+++ b/tests/unit/com/android/documentsui/dirlist/DragHostTest.java
@@ -20,18 +20,18 @@ import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertTrue;
 
 import android.content.ClipData;
-import android.database.Cursor;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
 import android.view.DragEvent;
 import android.view.View;
 
+import androidx.recyclerview.selection.SelectionTracker;
+
+import com.android.documentsui.SelectionHelpers;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.files.TestActivity;
-import com.android.documentsui.selection.SelectionHelper;
 import com.android.documentsui.testing.ClipDatas;
 import com.android.documentsui.testing.DragEvents;
-import com.android.documentsui.testing.SelectionHelpers;
 import com.android.documentsui.testing.TestActionHandler;
 import com.android.documentsui.testing.TestDragAndDropManager;
 import com.android.documentsui.testing.TestEnv;
@@ -55,7 +55,7 @@ public class DragHostTest {
     private TestDialogController mDialogs;
     private DragHost<?> dragHost;
     private TestDragAndDropManager mDragAndDropManager;
-    private SelectionHelper mSelectionMgr;
+    private SelectionTracker<String> mSelectionMgr;
     private boolean mIsDocumentView;
     private DocumentHolder mNextDocumentHolder;
     private DocumentInfo mNextDocumentInfo;
diff --git a/tests/unit/com/android/documentsui/dirlist/DragStartListenerTest.java b/tests/unit/com/android/documentsui/dirlist/DragStartListenerTest.java
index faa86a394..b5739763b 100644
--- a/tests/unit/com/android/documentsui/dirlist/DragStartListenerTest.java
+++ b/tests/unit/com/android/documentsui/dirlist/DragStartListenerTest.java
@@ -18,7 +18,6 @@ package com.android.documentsui.dirlist;
 
 import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertTrue;
-import static junit.framework.Assert.fail;
 
 import android.provider.DocumentsContract;
 import android.support.test.filters.SmallTest;
@@ -26,22 +25,21 @@ import android.support.test.runner.AndroidJUnit4;
 import android.view.MotionEvent;
 import android.view.View;
 
+import androidx.recyclerview.selection.MutableSelection;
+import androidx.recyclerview.selection.Selection;
+
 import com.android.documentsui.DocsSelectionHelper;
 import com.android.documentsui.MenuManager.SelectionDetails;
+import com.android.documentsui.SelectionHelpers;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.Events;
 import com.android.documentsui.base.Providers;
 import com.android.documentsui.base.State;
 import com.android.documentsui.dirlist.DragStartListener.RuntimeDragStartListener;
-import com.android.documentsui.selection.MutableSelection;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.TestItemDetailsLookup;
-import com.android.documentsui.testing.SelectionHelpers;
 import com.android.documentsui.testing.TestDragAndDropManager;
 import com.android.documentsui.testing.TestEvents;
 import com.android.documentsui.testing.TestSelectionDetails;
 import com.android.documentsui.testing.Views;
-import com.android.internal.widget.RecyclerView;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -79,7 +77,6 @@ public class DragStartListenerTest {
         mListener = new DragStartListener.RuntimeDragStartListener(
                 null, // icon helper
                 state,
-                mDocLookup,
                 mSelectionMgr,
                 mSelectionDetails,
                 // view finder
@@ -91,7 +88,7 @@ public class DragStartListenerTest {
                     return mViewModelId;
                 },
                 // docInfo Converter
-                (Selection selection) -> {
+                (Selection<String> selection) -> {
                     return new ArrayList<>();
                 },
                 mManager);
@@ -107,47 +104,29 @@ public class DragStartListenerTest {
 
     @Test
     public void testMouseEvent() {
-        assertTrue(Events.isMouseDragEvent(mEvent.build()));
+        MotionEvent e = mEvent.build();
+        // Assert it is a mouse drag event.
+        assertTrue(Events.isMouseEvent(e));
+        assertTrue(e.getActionMasked() == MotionEvent.ACTION_MOVE);
+        assertTrue(e.isButtonPressed(MotionEvent.BUTTON_PRIMARY));
     }
 
     @Test
     public void testDragStarted_OnMouseMove() {
-        assertTrue(mListener.onMouseDragEvent(mEvent.build()));
+        assertTrue(mListener.onDragEvent(mEvent.build()));
         mManager.startDragHandler.assertCalled();
     }
 
     @Test
     public void testDragNotStarted_NonModelBackedView() {
         mViewModelId = null;
-        assertFalse(mListener.onMouseDragEvent(mEvent.build()));
+        assertFalse(mListener.onDragEvent(mEvent.build()));
         mManager.startDragHandler.assertNotCalled();
     }
 
     @Test
-    public void testThrows_OnNonMouseMove() {
-        assertThrows(mEvent.touch().build());
-    }
-
-    @Test
-    public void testThrows_OnNonPrimaryMove() {
-        mEvent.releaseButton(MotionEvent.BUTTON_PRIMARY);
-        assertThrows(mEvent.pressButton(MotionEvent.BUTTON_SECONDARY).build());
-    }
-
-    @Test
-    public void testThrows_OnNonMove() {
-        assertThrows(mEvent.action(MotionEvent.ACTION_UP).build());
-    }
-
-    @Test
-    public void testThrows_WhenNotOnItem() {
-        mDocLookup.initAt(RecyclerView.NO_POSITION);
-        assertThrows(mEvent.build());
-    }
-
-    @Test
     public void testDragStart_nonSelectedItem() {
-        Selection selection = mListener.getSelectionToBeCopied("1234",
+        Selection<String> selection = mListener.getSelectionToBeCopied("1234",
                 mEvent.action(MotionEvent.ACTION_MOVE).build());
         assertTrue(selection.size() == 1);
         assertTrue(selection.contains("1234"));
@@ -155,7 +134,7 @@ public class DragStartListenerTest {
 
     @Test
     public void testDragStart_selectedItem() {
-        MutableSelection selection = new MutableSelection();
+        MutableSelection<String> selection = new MutableSelection<>();
         selection.add("1234");
         selection.add("5678");
         mSelectionMgr.replaceSelection(selection);
@@ -169,7 +148,7 @@ public class DragStartListenerTest {
 
     @Test
     public void testDragStart_newNonSelectedItem() {
-        MutableSelection selection = new MutableSelection();
+        MutableSelection<String> selection = new MutableSelection<>();
         selection.add("5678");
         mSelectionMgr.replaceSelection(selection);
 
@@ -183,7 +162,7 @@ public class DragStartListenerTest {
 
     @Test
     public void testCtrlDragStart_newNonSelectedItem() {
-        MutableSelection selection = new MutableSelection();
+        MutableSelection<String> selection = new MutableSelection<>();
         selection.add("5678");
         mSelectionMgr.replaceSelection(selection);
 
@@ -193,11 +172,4 @@ public class DragStartListenerTest {
         assertTrue(selection.contains("1234"));
         assertTrue(selection.contains("5678"));
     }
-
-    private void assertThrows(MotionEvent e) {
-        try {
-            mListener.onMouseDragEvent(e);
-            fail();
-        } catch (IllegalArgumentException expected) {}
-    }
 }
diff --git a/tests/unit/com/android/documentsui/dirlist/KeyInputHandlerTest.java b/tests/unit/com/android/documentsui/dirlist/KeyInputHandlerTest.java
index e0313dab2..58ecf8be9 100644
--- a/tests/unit/com/android/documentsui/dirlist/KeyInputHandlerTest.java
+++ b/tests/unit/com/android/documentsui/dirlist/KeyInputHandlerTest.java
@@ -18,17 +18,15 @@ package com.android.documentsui.dirlist;
 
 import static org.junit.Assert.assertEquals;
 
-import androidx.annotation.Nullable;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
 import android.view.KeyEvent;
 
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-import com.android.documentsui.selection.testing.SelectionPredicates;
-import com.android.documentsui.selection.testing.SelectionProbe;
-import com.android.documentsui.selection.testing.TestData;
-import com.android.documentsui.testing.SelectionHelpers;
+import androidx.annotation.Nullable;
+import androidx.recyclerview.selection.Selection;
+import androidx.recyclerview.selection.SelectionTracker;
+
+import com.android.documentsui.SelectionHelpers;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -43,21 +41,19 @@ public final class KeyInputHandlerTest {
     private static final List<String> ITEMS = TestData.create(100);
 
     private KeyInputHandler mInputHandler;
-    private SelectionHelper mSelectionHelper;
+    private SelectionTracker<String> mSelectionHelper;
     private TestFocusHandler mFocusHandler;
-    private SelectionProbe mSelection;
     private TestCallbacks mCallbacks;
 
     @Before
     public void setUp() {
         mSelectionHelper = SelectionHelpers.createTestInstance(ITEMS);
-        mSelection = new SelectionProbe(mSelectionHelper);
         mFocusHandler = new TestFocusHandler();
         mCallbacks = new TestCallbacks();
 
         mInputHandler = new KeyInputHandler(
                 mSelectionHelper,
-                SelectionPredicates.CAN_SET_ANYTHING,
+                SelectionHelpers.CAN_SET_ANYTHING,
                 mCallbacks);
     }
 
@@ -69,34 +65,32 @@ public final class KeyInputHandlerTest {
         KeyEvent event = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DPAD_UP);
         mInputHandler.onKey(null, event.getKeyCode(), event);
 
-        mSelection.assertNoSelection();
+        Selection<String> selection = mSelectionHelper.getSelection();
+        assertEquals(selection.toString(), 0, selection.size());
     }
 
-    private static final class TestCallbacks extends KeyInputHandler.Callbacks {
+    private static final class TestCallbacks
+            extends KeyInputHandler.Callbacks<DocumentItemDetails> {
 
-        private @Nullable ItemDetails mActivated;
+        private @Nullable DocumentItemDetails mActivated;
 
         @Override
-        public boolean isInteractiveItem(ItemDetails item, KeyEvent e) {
+        public boolean isInteractiveItem(DocumentItemDetails item, KeyEvent e) {
             return true;
         }
 
         @Override
-        public boolean onItemActivated(ItemDetails item, KeyEvent e) {
+        public boolean onItemActivated(DocumentItemDetails item, KeyEvent e) {
             mActivated = item;
             return false;
         }
 
-        private void assertActivated(ItemDetails expected) {
+        private void assertActivated(DocumentItemDetails expected) {
             assertEquals(expected, mActivated);
         }
 
         @Override
-        public void onPerformHapticFeedback() {
-        }
-
-        @Override
-        public boolean onFocusItem(ItemDetails details, int keyCode, KeyEvent event) {
+        public boolean onFocusItem(DocumentItemDetails details, int keyCode, KeyEvent event) {
             return true;
         }
     }
diff --git a/tests/unit/com/android/documentsui/selection/TestItemDetails.java b/tests/unit/com/android/documentsui/dirlist/TestItemDetails.java
index b943247d5..75e8e2409 100644
--- a/tests/unit/com/android/documentsui/selection/TestItemDetails.java
+++ b/tests/unit/com/android/documentsui/dirlist/TestItemDetails.java
@@ -13,14 +13,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.android.documentsui.selection;
+package com.android.documentsui.dirlist;
 
 import android.view.MotionEvent;
 
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails;
+
 import com.android.internal.widget.RecyclerView;
 
-public final class TestItemDetails extends ItemDetails {
+/**
+ * Test implementation of ItemDetails.
+ */
+public final class TestItemDetails extends ItemDetails<String> {
 
     // DocumentsAdapter.ITEM_TYPE_DOCUMENT
     private int mViewType = -1;
@@ -60,7 +64,6 @@ public final class TestItemDetails extends ItemDetails {
         mInSelectionHotspot = over;
     }
 
-    @Override
     public int getItemViewType() {
         return mViewType;
     }
@@ -97,7 +100,7 @@ public final class TestItemDetails extends ItemDetails {
     }
 
     @Override
-    public String getStableId() {
+    public String getSelectionKey() {
         return mStableId;
     }
 
diff --git a/tests/unit/com/android/documentsui/selection/TestItemDetailsLookup.java b/tests/unit/com/android/documentsui/dirlist/TestItemDetailsLookup.java
index 66014ceaa..3ae3e2663 100644
--- a/tests/unit/com/android/documentsui/selection/TestItemDetailsLookup.java
+++ b/tests/unit/com/android/documentsui/dirlist/TestItemDetailsLookup.java
@@ -13,47 +13,23 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.android.documentsui.selection;
+package com.android.documentsui.dirlist;
 
-import androidx.recyclerview.widget.RecyclerView;
 import android.view.MotionEvent;
 
+import com.android.documentsui.DocsSelectionHelper.DocDetailsLookup;
+
 import javax.annotation.Nullable;
 
 /**
- * Test impl of ItemDetailsLookup.
+ * Test implementation of ItemDetailsLookup.
  */
-public class TestItemDetailsLookup extends ItemDetailsLookup {
+public class TestItemDetailsLookup extends DocDetailsLookup {
 
     private @Nullable TestItemDetails mDoc;
 
     @Override
-    public boolean overItem(MotionEvent e) {
-        return getItemPosition(e) != RecyclerView.NO_POSITION;
-    }
-
-    @Override
-    public boolean overStableItem(MotionEvent e) {
-        return mDoc.getStableId() != null;
-    }
-
-    @Override
-    public boolean inItemDragRegion(MotionEvent e) {
-        return mDoc.inDragRegion(e);
-    }
-
-    @Override
-    public int getItemPosition(MotionEvent e) {
-        return mDoc.getPosition();
-    }
-
-    @Override
-    public boolean inItemSelectRegion(MotionEvent e) {
-        return mDoc.inSelectionHotspot(e);
-    }
-
-    @Override
-    public @Nullable ItemDetails getItemDetails(MotionEvent e) {
+    public @Nullable ItemDetails<String> getItemDetails(MotionEvent e) {
         return mDoc;
     }
 
diff --git a/tests/unit/com/android/documentsui/files/MenuManagerTest.java b/tests/unit/com/android/documentsui/files/MenuManagerTest.java
index 957a7318b..6cb3c5013 100644
--- a/tests/unit/com/android/documentsui/files/MenuManagerTest.java
+++ b/tests/unit/com/android/documentsui/files/MenuManagerTest.java
@@ -24,16 +24,15 @@ import android.provider.DocumentsContract.Document;
 import android.provider.DocumentsContract.Root;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
-import android.test.AndroidTestCase;
+
+import androidx.recyclerview.selection.SelectionTracker;
 
 import com.android.documentsui.R;
+import com.android.documentsui.SelectionHelpers;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.base.State;
-import com.android.documentsui.dirlist.TestContext;
 import com.android.documentsui.dirlist.TestData;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.testing.SelectionHelpers;
 import com.android.documentsui.testing.TestDirectoryDetails;
 import com.android.documentsui.testing.TestEnv;
 import com.android.documentsui.testing.TestFeatures;
@@ -112,7 +111,7 @@ public final class MenuManagerTest {
     private State state = new State();
     private MenuManager mgr;
     private TestActivity activity = TestActivity.create(TestEnv.create());
-    private SelectionHelper selectionManager;
+    private SelectionTracker<String> selectionManager;
 
     @Before
     public void setUp() {
diff --git a/tests/unit/com/android/documentsui/selection/BandSelectionHelperTest.java b/tests/unit/com/android/documentsui/selection/BandSelectionHelperTest.java
deleted file mode 100644
index 62c6f769e..000000000
--- a/tests/unit/com/android/documentsui/selection/BandSelectionHelperTest.java
+++ /dev/null
@@ -1,298 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import android.graphics.Point;
-import android.graphics.Rect;
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import androidx.recyclerview.widget.RecyclerView.OnScrollListener;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.BandSelectionHelper.BandHost;
-import com.android.documentsui.selection.testing.SelectionPredicates;
-import com.android.documentsui.selection.testing.TestAdapter;
-import com.android.documentsui.selection.testing.TestBandPredicate;
-import com.android.documentsui.selection.testing.TestEvents.Builder;
-import com.android.documentsui.selection.testing.TestStableIdProvider;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.Collections;
-import java.util.List;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class BandSelectionHelperTest {
-
-    private List<String> mItems;
-    private BandSelectionHelper mBandController;
-    private boolean mIsActive;
-    private Builder mStartBuilder;
-    private Builder mStopBuilder;
-    private MotionEvent mStartEvent;
-    private MotionEvent mStopEvent;
-    private TestBandHost mBandHost;
-    private TestBandPredicate mBandPredicate;
-
-    @Before
-    public void setup() throws Exception {
-        mItems = TestAdapter.createItemList(10);
-        mIsActive = false;
-        TestAdapter adapter = new TestAdapter();
-        adapter.updateTestModelIds(mItems);
-        mBandHost = new TestBandHost();
-        mBandPredicate = new TestBandPredicate();
-
-        SelectionHelper helper = new DefaultSelectionHelper(
-                DefaultSelectionHelper.MODE_SINGLE,
-                adapter,
-                new TestStableIdProvider(adapter),
-                SelectionPredicates.CAN_SET_ANYTHING);
-
-        mBandController = new BandSelectionHelper(
-                mBandHost,
-                adapter,
-                new TestStableIdProvider(adapter),
-                helper,
-                SelectionPredicates.CAN_SET_ANYTHING,
-                mBandPredicate,
-                new ContentLock()) {
-                    @Override
-                    public boolean isActive() {
-                        return mIsActive;
-                    }
-                };
-
-        mStartBuilder = new Builder().mouse().primary().action(MotionEvent.ACTION_MOVE);
-        mStopBuilder = new Builder().mouse().action(MotionEvent.ACTION_UP);
-        mStartEvent = mStartBuilder.build();
-        mStopEvent = mStopBuilder.build();
-    }
-
-    @Test
-    public void testGoodStart() {
-        assertTrue(mBandController.shouldStart(mStartEvent));
-    }
-
-    @Test
-    public void testBadStart_NoButtons() {
-        assertFalse(mBandController.shouldStart(
-                mStartBuilder.releaseButton(MotionEvent.BUTTON_PRIMARY).build()));
-    }
-
-    @Test
-    public void testBadStart_SecondaryButton() {
-        assertFalse(
-                mBandController.shouldStart(mStartBuilder.secondary().build()));
-    }
-
-    @Test
-    public void testBadStart_TertiaryButton() {
-        assertFalse(
-                mBandController.shouldStart(mStartBuilder.tertiary().build()));
-    }
-
-    @Test
-    public void testBadStart_Touch() {
-        assertFalse(mBandController.shouldStart(
-                mStartBuilder.touch().releaseButton(MotionEvent.BUTTON_PRIMARY).build()));
-    }
-
-    @Test
-    public void testBadStart_RespectsCanInitiateBand() {
-        mBandPredicate.setCanInitiate(false);
-        assertFalse(mBandController.shouldStart(mStartEvent));
-    }
-
-    @Test
-    public void testBadStart_ActionDown() {
-        assertFalse(mBandController
-                .shouldStart(mStartBuilder.action(MotionEvent.ACTION_DOWN).build()));
-    }
-
-    @Test
-    public void testBadStart_ActionUp() {
-        assertFalse(mBandController
-                .shouldStart(mStartBuilder.action(MotionEvent.ACTION_UP).build()));
-    }
-
-    @Test
-    public void testBadStart_ActionPointerDown() {
-        assertFalse(mBandController.shouldStart(
-                mStartBuilder.action(MotionEvent.ACTION_POINTER_DOWN).build()));
-    }
-
-    @Test
-    public void testBadStart_ActionPointerUp() {
-        assertFalse(mBandController.shouldStart(
-                mStartBuilder.action(MotionEvent.ACTION_POINTER_UP).build()));
-    }
-
-    @Test
-    public void testBadStart_NoItems() {
-        TestAdapter emptyAdapter = new TestAdapter();
-        emptyAdapter.updateTestModelIds(Collections.EMPTY_LIST);
-
-        SelectionHelper helper = new DefaultSelectionHelper(
-                DefaultSelectionHelper.MODE_SINGLE,
-                emptyAdapter,
-                new TestStableIdProvider(emptyAdapter),
-                SelectionPredicates.CAN_SET_ANYTHING);
-
-        mBandController = new BandSelectionHelper(
-                new TestBandHost(),
-                emptyAdapter,
-                new TestStableIdProvider(emptyAdapter),
-                helper,
-                SelectionPredicates.CAN_SET_ANYTHING,
-                mBandPredicate,
-                new ContentLock());
-
-        assertFalse(mBandController.shouldStart(mStartEvent));
-    }
-
-    @Test
-    public void testBadStart_alreadyActive() {
-        mIsActive = true;
-        assertFalse(mBandController.shouldStart(mStartEvent));
-    }
-
-    @Test
-    public void testGoodStop() {
-        mIsActive = true;
-        assertTrue(mBandController.shouldStop(mStopEvent));
-    }
-
-    @Test
-    public void testGoodStop_PointerUp() {
-        mIsActive = true;
-        assertTrue(mBandController
-                .shouldStop(mStopBuilder.action(MotionEvent.ACTION_POINTER_UP).build()));
-    }
-
-    @Test
-    public void testGoodStop_Cancel() {
-        mIsActive = true;
-        assertTrue(mBandController
-                .shouldStop(mStopBuilder.action(MotionEvent.ACTION_CANCEL).build()));
-    }
-
-    @Test
-    public void testBadStop_NotActive() {
-        assertFalse(mBandController.shouldStop(mStopEvent));
-    }
-
-    @Test
-    public void testBadStop_NonMouse() {
-        mIsActive = true;
-        assertFalse(mBandController.shouldStop(mStopBuilder.touch().build()));
-    }
-
-    @Test
-    public void testBadStop_Move() {
-        mIsActive = true;
-        assertFalse(mBandController.shouldStop(
-                mStopBuilder.action(MotionEvent.ACTION_MOVE).touch().build()));
-    }
-
-    @Test
-    public void testBadStop_Down() {
-        mIsActive = true;
-        assertFalse(mBandController.shouldStop(
-                mStopBuilder.action(MotionEvent.ACTION_DOWN).touch().build()));
-    }
-
-    private final class TestBandHost extends BandHost {
-        @Override
-        public void scrollBy(int dy) {
-        }
-
-        @Override
-        public void runAtNextFrame(Runnable r) {
-        }
-
-        @Override
-        public void removeCallback(Runnable r) {
-        }
-
-        @Override
-        public void showBand(Rect rect) {
-        }
-
-        @Override
-        public void hideBand() {
-        }
-
-        @Override
-        public void addOnScrollListener(OnScrollListener listener) {
-        }
-
-        @Override
-        public void removeOnScrollListener(OnScrollListener listener) {
-        }
-
-        @Override
-        public int getHeight() {
-            return 0;
-        }
-
-        @Override
-        public void invalidateView() {
-        }
-
-        @Override
-        public Point createAbsolutePoint(Point relativePoint) {
-            return null;
-        }
-
-        @Override
-        public Rect getAbsoluteRectForChildViewAt(int index) {
-            return null;
-        }
-
-        @Override
-        public int getAdapterPositionAt(int index) {
-            return 0;
-        }
-
-        @Override
-        public int getColumnCount() {
-            return 0;
-        }
-
-        @Override
-        public int getChildCount() {
-            return 0;
-        }
-
-        @Override
-        public int getVisibleChildCount() {
-            return 0;
-        }
-
-        @Override
-        public boolean hasView(int adapterPosition) {
-            return false;
-        }
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/ContentLockTest.java b/tests/unit/com/android/documentsui/selection/ContentLockTest.java
deleted file mode 100644
index 71b6b0fb0..000000000
--- a/tests/unit/com/android/documentsui/selection/ContentLockTest.java
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class ContentLockTest {
-
-    private ContentLock mLock = new ContentLock();
-    private boolean mCalled;
-
-    private Runnable mRunnable = new Runnable() {
-        @Override
-        public void run() {
-            mCalled = true;
-        }
-    };
-
-    @Before
-    public void setUp() {
-        mCalled = false;
-    }
-
-    @Test
-    public void testNotBlocking_callbackNotBlocked() {
-        mLock.runWhenUnlocked(mRunnable);
-        assertTrue(mCalled);
-    }
-
-    @Test
-    public void testToggleBlocking_callbackNotBlocked() {
-        mLock.block();
-        mLock.unblock();
-        mLock.runWhenUnlocked(mRunnable);
-        assertTrue(mCalled);
-    }
-
-    @Test
-    public void testBlocking_callbackBlocked() {
-        mLock.block();
-        mLock.runWhenUnlocked(mRunnable);
-        assertFalse(mCalled);
-    }
-
-    @Test
-    public void testBlockthenUnblock_callbackNotBlocked() {
-        mLock.block();
-        mLock.runWhenUnlocked(mRunnable);
-        mLock.unblock();
-        assertTrue(mCalled);
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/DefaultSelectionHelperTest.java b/tests/unit/com/android/documentsui/selection/DefaultSelectionHelperTest.java
deleted file mode 100644
index 48c0b2af0..000000000
--- a/tests/unit/com/android/documentsui/selection/DefaultSelectionHelperTest.java
+++ /dev/null
@@ -1,409 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-import static org.junit.Assert.assertFalse;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import android.util.SparseBooleanArray;
-
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-import com.android.documentsui.selection.testing.SelectionProbe;
-import com.android.documentsui.selection.testing.TestAdapter;
-import com.android.documentsui.selection.testing.TestSelectionObserver;
-import com.android.documentsui.selection.testing.TestStableIdProvider;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class DefaultSelectionHelperTest {
-
-    private List<String> mItems;
-    private Set<String> mIgnored;
-    private TestAdapter mAdapter;
-    private DefaultSelectionHelper mHelper;
-    private TestSelectionObserver mListener;
-    private SelectionProbe mSelection;
-
-    @Before
-    public void setUp() throws Exception {
-        mIgnored = new HashSet<>();
-        mItems = TestAdapter.createItemList(100);
-        mListener = new TestSelectionObserver();
-        mAdapter = new TestAdapter();
-        mAdapter.updateTestModelIds(mItems);
-
-        SelectionPredicate canSelect = new SelectionPredicate() {
-
-            @Override
-            public boolean canSetStateForId(String id, boolean nextState) {
-                return !nextState || !mIgnored.contains(id);
-            }
-
-            @Override
-            public boolean canSetStateAtPosition(int position, boolean nextState) {
-                throw new UnsupportedOperationException("Not implemented.");
-            }
-        };
-        mHelper = new DefaultSelectionHelper(
-                DefaultSelectionHelper.MODE_MULTIPLE,
-                mAdapter,
-                new TestStableIdProvider(mAdapter),
-                canSelect);
-
-        mHelper.addObserver(mListener);
-
-        mSelection = new SelectionProbe(mHelper, mListener);
-
-        mIgnored.clear();
-    }
-
-    @Test
-    public void testSelect() {
-        mHelper.select(mItems.get(7));
-
-        mSelection.assertSelection(7);
-    }
-
-    @Test
-    public void testDeselect() {
-        mHelper.select(mItems.get(7));
-        mHelper.deselect(mItems.get(7));
-
-        mSelection.assertNoSelection();
-    }
-
-    @Test
-    public void testSelection_DoNothingOnUnselectableItem() {
-        mIgnored.add(mItems.get(7));
-        boolean selected = mHelper.select(mItems.get(7));
-
-        assertFalse(selected);
-        mSelection.assertNoSelection();
-    }
-
-    @Test
-    public void testSelect_NotifiesListenersOfChange() {
-        mHelper.select(mItems.get(7));
-
-        mListener.assertSelectionChanged();
-    }
-
-    @Test
-    public void testSelect_NotifiesAdapterOfSelect() {
-        mHelper.select(mItems.get(7));
-
-        mAdapter.assertNotifiedOfSelectionChange(7);
-    }
-
-    @Test
-    public void testSelect_NotifiesAdapterOfDeselect() {
-        mHelper.select(mItems.get(7));
-        mAdapter.resetSelectionNotifications();
-        mHelper.deselect(mItems.get(7));
-        mAdapter.assertNotifiedOfSelectionChange(7);
-    }
-
-    @Test
-    public void testDeselect_NotifiesSelectionChanged() {
-        mHelper.select(mItems.get(7));
-        mHelper.deselect(mItems.get(7));
-
-        mListener.assertSelectionChanged();
-    }
-
-    @Test
-    public void testSelection_PersistsOnUpdate() {
-        mHelper.select(mItems.get(7));
-        mAdapter.updateTestModelIds(mItems);
-
-        mSelection.assertSelection(7);
-    }
-
-    @Test
-    public void testSelection_IntersectsWithNewDataSet() {
-        mHelper.select(mItems.get(99));
-        mHelper.select(mItems.get(7));
-
-        mAdapter.updateTestModelIds(TestAdapter.createItemList(50));
-
-        mSelection.assertSelection(7);
-    }
-
-    @Test
-    public void testSetItemsSelected() {
-        mHelper.setItemsSelected(getStringIds(6, 7, 8), true);
-
-        mSelection.assertRangeSelected(6, 8);
-    }
-
-    @Test
-    public void testSetItemsSelected_SkipUnselectableItem() {
-        mIgnored.add(mItems.get(7));
-
-        mHelper.setItemsSelected(getStringIds(6, 7, 8), true);
-
-        mSelection.assertSelected(6);
-        mSelection.assertNotSelected(7);
-        mSelection.assertSelected(8);
-    }
-
-    @Test
-    public void testRangeSelection() {
-        mHelper.startRange(15);
-        mHelper.extendRange(19);
-        mSelection.assertRangeSelection(15, 19);
-    }
-
-    @Test
-    public void testRangeSelection_SkipUnselectableItem() {
-        mIgnored.add(mItems.get(17));
-
-        mHelper.startRange(15);
-        mHelper.extendRange(19);
-
-        mSelection.assertRangeSelected(15, 16);
-        mSelection.assertNotSelected(17);
-        mSelection.assertRangeSelected(18, 19);
-    }
-
-    @Test
-    public void testRangeSelection_snapExpand() {
-        mHelper.startRange(15);
-        mHelper.extendRange(19);
-        mHelper.extendRange(27);
-        mSelection.assertRangeSelection(15, 27);
-    }
-
-    @Test
-    public void testRangeSelection_snapContract() {
-        mHelper.startRange(15);
-        mHelper.extendRange(27);
-        mHelper.extendRange(19);
-        mSelection.assertRangeSelection(15, 19);
-    }
-
-    @Test
-    public void testRangeSelection_snapInvert() {
-        mHelper.startRange(15);
-        mHelper.extendRange(27);
-        mHelper.extendRange(3);
-        mSelection.assertRangeSelection(3, 15);
-    }
-
-    @Test
-    public void testRangeSelection_multiple() {
-        mHelper.startRange(15);
-        mHelper.extendRange(27);
-        mHelper.endRange();
-        mHelper.startRange(42);
-        mHelper.extendRange(57);
-        mSelection.assertSelectionSize(29);
-        mSelection.assertRangeSelected(15, 27);
-        mSelection.assertRangeSelected(42, 57);
-    }
-
-    @Test
-    public void testProvisionalRangeSelection() {
-        mHelper.startRange(13);
-        mHelper.extendProvisionalRange(15);
-        mSelection.assertRangeSelection(13, 15);
-        mHelper.getSelection().mergeProvisionalSelection();
-        mHelper.endRange();
-        mSelection.assertSelectionSize(3);
-    }
-
-    @Test
-    public void testProvisionalRangeSelection_endEarly() {
-        mHelper.startRange(13);
-        mHelper.extendProvisionalRange(15);
-        mSelection.assertRangeSelection(13, 15);
-
-        mHelper.endRange();
-        // If we end range selection prematurely for provision selection, nothing should be selected
-        // except the first item
-        mSelection.assertSelectionSize(1);
-    }
-
-    @Test
-    public void testProvisionalRangeSelection_snapExpand() {
-        mHelper.startRange(13);
-        mHelper.extendProvisionalRange(15);
-        mSelection.assertRangeSelection(13, 15);
-        mHelper.getSelection().mergeProvisionalSelection();
-        mHelper.extendRange(18);
-        mSelection.assertRangeSelection(13, 18);
-    }
-
-    @Test
-    public void testCombinationRangeSelection_IntersectsOldSelection() {
-        mHelper.startRange(13);
-        mHelper.extendRange(15);
-        mSelection.assertRangeSelection(13, 15);
-
-        mHelper.startRange(11);
-        mHelper.extendProvisionalRange(18);
-        mSelection.assertRangeSelected(11, 18);
-        mHelper.endRange();
-        mSelection.assertRangeSelected(13, 15);
-        mSelection.assertRangeSelected(11, 11);
-        mSelection.assertSelectionSize(4);
-    }
-
-    @Test
-    public void testProvisionalSelection() {
-        Selection s = mHelper.getSelection();
-        mSelection.assertNoSelection();
-
-        // Mimicking band selection case -- BandController notifies item callback by itself.
-        mListener.onItemStateChanged(mItems.get(1), true);
-        mListener.onItemStateChanged(mItems.get(2), true);
-
-        SparseBooleanArray provisional = new SparseBooleanArray();
-        provisional.append(1, true);
-        provisional.append(2, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-        mSelection.assertSelection(1, 2);
-    }
-
-    @Test
-    public void testProvisionalSelection_Replace() {
-        Selection s = mHelper.getSelection();
-
-        // Mimicking band selection case -- BandController notifies item callback by itself.
-        mListener.onItemStateChanged(mItems.get(1), true);
-        mListener.onItemStateChanged(mItems.get(2), true);
-        SparseBooleanArray provisional = new SparseBooleanArray();
-        provisional.append(1, true);
-        provisional.append(2, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-
-        mListener.onItemStateChanged(mItems.get(1), false);
-        mListener.onItemStateChanged(mItems.get(2), false);
-        provisional.clear();
-
-        mListener.onItemStateChanged(mItems.get(3), true);
-        mListener.onItemStateChanged(mItems.get(4), true);
-        provisional.append(3, true);
-        provisional.append(4, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-        mSelection.assertSelection(3, 4);
-    }
-
-    @Test
-    public void testProvisionalSelection_IntersectsExistingProvisionalSelection() {
-        Selection s = mHelper.getSelection();
-
-        // Mimicking band selection case -- BandController notifies item callback by itself.
-        mListener.onItemStateChanged(mItems.get(1), true);
-        mListener.onItemStateChanged(mItems.get(2), true);
-        SparseBooleanArray provisional = new SparseBooleanArray();
-        provisional.append(1, true);
-        provisional.append(2, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-
-        mListener.onItemStateChanged(mItems.get(1), false);
-        mListener.onItemStateChanged(mItems.get(2), false);
-        provisional.clear();
-
-        mListener.onItemStateChanged(mItems.get(1), true);
-        provisional.append(1, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-        mSelection.assertSelection(1);
-    }
-
-    @Test
-    public void testProvisionalSelection_Apply() {
-        Selection s = mHelper.getSelection();
-
-        // Mimicking band selection case -- BandController notifies item callback by itself.
-        mListener.onItemStateChanged(mItems.get(1), true);
-        mListener.onItemStateChanged(mItems.get(2), true);
-        SparseBooleanArray provisional = new SparseBooleanArray();
-        provisional.append(1, true);
-        provisional.append(2, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-        s.mergeProvisionalSelection();
-
-        mSelection.assertSelection(1, 2);
-    }
-
-    @Test
-    public void testProvisionalSelection_Cancel() {
-        mHelper.select(mItems.get(1));
-        mHelper.select(mItems.get(2));
-        Selection s = mHelper.getSelection();
-
-        SparseBooleanArray provisional = new SparseBooleanArray();
-        provisional.append(3, true);
-        provisional.append(4, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-        s.clearProvisionalSelection();
-
-        // Original selection should remain.
-        mSelection.assertSelection(1, 2);
-    }
-
-    @Test
-    public void testProvisionalSelection_IntersectsAppliedSelection() {
-        mHelper.select(mItems.get(1));
-        mHelper.select(mItems.get(2));
-        Selection s = mHelper.getSelection();
-
-        // Mimicking band selection case -- BandController notifies item callback by itself.
-        mListener.onItemStateChanged(mItems.get(3), true);
-        SparseBooleanArray provisional = new SparseBooleanArray();
-        provisional.append(2, true);
-        provisional.append(3, true);
-        s.setProvisionalSelection(getItemIds(provisional));
-        mSelection.assertSelection(1, 2, 3);
-    }
-
-    @Test
-    public void testObserverOnChanged_NotifiesListenersOfChange() {
-        mAdapter.notifyDataSetChanged();
-
-        mListener.assertSelectionChanged();
-    }
-
-    private Set<String> getItemIds(SparseBooleanArray selection) {
-        Set<String> ids = new HashSet<>();
-
-        int count = selection.size();
-        for (int i = 0; i < count; ++i) {
-            ids.add(mItems.get(selection.keyAt(i)));
-        }
-
-        return ids;
-    }
-
-    private Iterable<String> getStringIds(int... ids) {
-        List<String> stringIds = new ArrayList<>(ids.length);
-        for (int id : ids) {
-            stringIds.add(mItems.get(id));
-        }
-        return stringIds;
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/DefaultSelectionHelper_SingleSelectTest.java b/tests/unit/com/android/documentsui/selection/DefaultSelectionHelper_SingleSelectTest.java
deleted file mode 100644
index 563ce87df..000000000
--- a/tests/unit/com/android/documentsui/selection/DefaultSelectionHelper_SingleSelectTest.java
+++ /dev/null
@@ -1,84 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static org.junit.Assert.fail;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-
-import com.android.documentsui.selection.testing.SelectionPredicates;
-import com.android.documentsui.selection.testing.SelectionProbe;
-import com.android.documentsui.selection.testing.TestAdapter;
-import com.android.documentsui.selection.testing.TestSelectionObserver;
-import com.android.documentsui.selection.testing.TestStableIdProvider;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.List;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class DefaultSelectionHelper_SingleSelectTest {
-
-    private List<String> mItems;
-    private SelectionHelper mHelper;
-    private TestSelectionObserver mListener;
-    private SelectionProbe mSelection;
-
-    @Before
-    public void setUp() throws Exception {
-        mItems = TestAdapter.createItemList(100);
-        mListener = new TestSelectionObserver();
-        TestAdapter adapter = new TestAdapter();
-        adapter.updateTestModelIds(mItems);
-
-        mHelper = new DefaultSelectionHelper(
-                DefaultSelectionHelper.MODE_SINGLE,
-                adapter,
-                new TestStableIdProvider(adapter),
-                SelectionPredicates.CAN_SET_ANYTHING);
-
-        mHelper.addObserver(mListener);
-
-        mSelection = new SelectionProbe(mHelper);
-    }
-
-    @Test
-    public void testSimpleSelect() {
-        mHelper.select(mItems.get(3));
-        mHelper.select(mItems.get(4));
-        mListener.assertSelectionChanged();
-        mSelection.assertSelection(4);
-    }
-
-    @Test
-    public void testRangeSelectionNotEstablished() {
-        mHelper.select(mItems.get(3));
-        mListener.reset();
-
-        try {
-            mHelper.extendRange(10);
-            fail("Should have thrown.");
-        } catch (Exception expected) {}
-
-        mListener.assertSelectionUnchanged();
-        mSelection.assertSelection(3);
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/GestureRouterTest.java b/tests/unit/com/android/documentsui/selection/GestureRouterTest.java
deleted file mode 100644
index e467f0fd0..000000000
--- a/tests/unit/com/android/documentsui/selection/GestureRouterTest.java
+++ /dev/null
@@ -1,285 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static org.mockito.Matchers.any;
-import static org.mockito.Matchers.anyFloat;
-import static org.mockito.Mockito.never;
-import static org.mockito.Mockito.verify;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import android.view.GestureDetector.OnDoubleTapListener;
-import android.view.GestureDetector.OnGestureListener;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.testing.TestEvents.Mouse;
-import com.android.documentsui.selection.testing.TestEvents.Touch;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.Mockito;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public final class GestureRouterTest {
-
-    private TestHandler mHandler;
-    private TestHandler mAlt;
-    private GestureRouter<TestHandler> mRouter;
-
-    @Before
-    public void setUp() {
-        mAlt = new TestHandler();
-        mHandler = new TestHandler();
-    }
-
-    @Test
-    public void testDelegates() {
-        mRouter = new GestureRouter<>();
-        mRouter.register(MotionEvent.TOOL_TYPE_MOUSE, mHandler);
-        mRouter.register(MotionEvent.TOOL_TYPE_FINGER, mAlt);
-
-        mRouter.onDown(Mouse.CLICK);
-        mHandler.assertCalled_onDown(Mouse.CLICK);
-        mAlt.assertNotCalled_onDown();
-
-        mRouter.onShowPress(Mouse.CLICK);
-        mHandler.assertCalled_onShowPress(Mouse.CLICK);
-        mAlt.assertNotCalled_onShowPress();
-
-        mRouter.onSingleTapUp(Mouse.CLICK);
-        mHandler.assertCalled_onSingleTapUp(Mouse.CLICK);
-        mAlt.assertNotCalled_onSingleTapUp();
-
-        mRouter.onScroll(null, Mouse.CLICK, -1, -1);
-        mHandler.assertCalled_onScroll(null, Mouse.CLICK, -1, -1);
-        mAlt.assertNotCalled_onScroll();
-
-        mRouter.onLongPress(Mouse.CLICK);
-        mHandler.assertCalled_onLongPress(Mouse.CLICK);
-        mAlt.assertNotCalled_onLongPress();
-
-        mRouter.onFling(null, Mouse.CLICK, -1, -1);
-        mHandler.assertCalled_onFling(null, Mouse.CLICK, -1, -1);
-        mAlt.assertNotCalled_onFling();
-
-        mRouter.onSingleTapConfirmed(Mouse.CLICK);
-        mHandler.assertCalled_onSingleTapConfirmed(Mouse.CLICK);
-        mAlt.assertNotCalled_onSingleTapConfirmed();
-
-        mRouter.onDoubleTap(Mouse.CLICK);
-        mHandler.assertCalled_onDoubleTap(Mouse.CLICK);
-        mAlt.assertNotCalled_onDoubleTap();
-
-        mRouter.onDoubleTapEvent(Mouse.CLICK);
-        mHandler.assertCalled_onDoubleTapEvent(Mouse.CLICK);
-        mAlt.assertNotCalled_onDoubleTapEvent();
-    }
-
-    @Test
-    public void testFallsback() {
-        mRouter = new GestureRouter<>(mAlt);
-        mRouter.register(MotionEvent.TOOL_TYPE_MOUSE, mHandler);
-
-        mRouter.onDown(Touch.TAP);
-        mAlt.assertCalled_onDown(Touch.TAP);
-
-        mRouter.onShowPress(Touch.TAP);
-        mAlt.assertCalled_onShowPress(Touch.TAP);
-
-        mRouter.onSingleTapUp(Touch.TAP);
-        mAlt.assertCalled_onSingleTapUp(Touch.TAP);
-
-        mRouter.onScroll(null, Touch.TAP, -1, -1);
-        mAlt.assertCalled_onScroll(null, Touch.TAP, -1, -1);
-
-        mRouter.onLongPress(Touch.TAP);
-        mAlt.assertCalled_onLongPress(Touch.TAP);
-
-        mRouter.onFling(null, Touch.TAP, -1, -1);
-        mAlt.assertCalled_onFling(null, Touch.TAP, -1, -1);
-
-        mRouter.onSingleTapConfirmed(Touch.TAP);
-        mAlt.assertCalled_onSingleTapConfirmed(Touch.TAP);
-
-        mRouter.onDoubleTap(Touch.TAP);
-        mAlt.assertCalled_onDoubleTap(Touch.TAP);
-
-        mRouter.onDoubleTapEvent(Touch.TAP);
-        mAlt.assertCalled_onDoubleTapEvent(Touch.TAP);
-    }
-
-    @Test
-    public void testEatsEventsWhenNoFallback() {
-        mRouter = new GestureRouter<>();
-        // Register the the delegate on mouse so touch events don't get handled.
-        mRouter.register(MotionEvent.TOOL_TYPE_MOUSE, mHandler);
-
-        mRouter.onDown(Touch.TAP);
-        mAlt.assertNotCalled_onDown();
-
-        mRouter.onShowPress(Touch.TAP);
-        mAlt.assertNotCalled_onShowPress();
-
-        mRouter.onSingleTapUp(Touch.TAP);
-        mAlt.assertNotCalled_onSingleTapUp();
-
-        mRouter.onScroll(null, Touch.TAP, -1, -1);
-        mAlt.assertNotCalled_onScroll();
-
-        mRouter.onLongPress(Touch.TAP);
-        mAlt.assertNotCalled_onLongPress();
-
-        mRouter.onFling(null, Touch.TAP, -1, -1);
-        mAlt.assertNotCalled_onFling();
-
-        mRouter.onSingleTapConfirmed(Touch.TAP);
-        mAlt.assertNotCalled_onSingleTapConfirmed();
-
-        mRouter.onDoubleTap(Touch.TAP);
-        mAlt.assertNotCalled_onDoubleTap();
-
-        mRouter.onDoubleTapEvent(Touch.TAP);
-        mAlt.assertNotCalled_onDoubleTapEvent();
-    }
-
-    private static final class TestHandler implements OnGestureListener, OnDoubleTapListener {
-
-        private final Spy mSpy = Mockito.mock(Spy.class);
-
-        @Override
-        public boolean onDown(MotionEvent e) {
-            return mSpy.onDown(e);
-        }
-
-        @Override
-        public void onShowPress(MotionEvent e) {
-            mSpy.onShowPress(e);
-        }
-
-        @Override
-        public boolean onSingleTapUp(MotionEvent e) {
-            return mSpy.onSingleTapUp(e);
-        }
-
-        @Override
-        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
-            return mSpy.onScroll(e1, e2, distanceX, distanceY);
-        }
-
-        @Override
-        public void onLongPress(MotionEvent e) {
-            mSpy.onLongPress(e);
-        }
-
-        @Override
-        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
-            return mSpy.onFling(e1, e2, velocityX, velocityY);
-        }
-
-        @Override
-        public boolean onSingleTapConfirmed(MotionEvent e) {
-            return mSpy.onSingleTapConfirmed(e);
-        }
-
-        @Override
-        public boolean onDoubleTap(MotionEvent e) {
-            return mSpy.onDoubleTap(e);
-        }
-
-        @Override
-        public boolean onDoubleTapEvent(MotionEvent e) {
-            return mSpy.onDoubleTapEvent(e);
-        }
-
-        void assertCalled_onDown(MotionEvent e) {
-            verify(mSpy).onDown(e);
-        }
-
-        void assertCalled_onShowPress(MotionEvent e) {
-            verify(mSpy).onShowPress(e);
-        }
-
-        void assertCalled_onSingleTapUp(MotionEvent e) {
-            verify(mSpy).onSingleTapUp(e);
-        }
-
-        void assertCalled_onScroll(MotionEvent e1, MotionEvent e2, float x, float y) {
-            verify(mSpy).onScroll(e1, e2, x, y);
-        }
-
-        void assertCalled_onLongPress(MotionEvent e) {
-            verify(mSpy).onLongPress(e);
-        }
-
-        void assertCalled_onFling(MotionEvent e1, MotionEvent e2, float x, float y) {
-            Mockito.verify(mSpy).onFling(e1, e2, x, y);
-        }
-
-        void assertCalled_onSingleTapConfirmed(MotionEvent e) {
-            Mockito.verify(mSpy).onSingleTapConfirmed(e);
-        }
-
-        void assertCalled_onDoubleTap(MotionEvent e) {
-            Mockito.verify(mSpy).onDoubleTap(e);
-        }
-
-        void assertCalled_onDoubleTapEvent(MotionEvent e) {
-            Mockito.verify(mSpy).onDoubleTapEvent(e);
-        }
-
-        void assertNotCalled_onDown() {
-            verify(mSpy, never()).onDown(any());
-        }
-
-        void assertNotCalled_onShowPress() {
-            verify(mSpy, never()).onShowPress(any());
-        }
-
-        void assertNotCalled_onSingleTapUp() {
-            verify(mSpy, never()).onSingleTapUp(any());
-        }
-
-        void assertNotCalled_onScroll() {
-            verify(mSpy, never()).onScroll(any(), any(), anyFloat(), anyFloat());
-        }
-
-        void assertNotCalled_onLongPress() {
-            verify(mSpy, never()).onLongPress(any());
-        }
-
-        void assertNotCalled_onFling() {
-            Mockito.verify(mSpy, never()).onFling(any(), any(), anyFloat(), anyFloat());
-        }
-
-        void assertNotCalled_onSingleTapConfirmed() {
-            Mockito.verify(mSpy, never()).onSingleTapConfirmed(any());
-        }
-
-        void assertNotCalled_onDoubleTap() {
-            Mockito.verify(mSpy, never()).onDoubleTap(any());
-        }
-
-        void assertNotCalled_onDoubleTapEvent() {
-            Mockito.verify(mSpy, never()).onDoubleTapEvent(any());
-        }
-    }
-
-    private static interface Spy extends OnGestureListener, OnDoubleTapListener {}
-}
diff --git a/tests/unit/com/android/documentsui/selection/GestureSelectionHelperTest.java b/tests/unit/com/android/documentsui/selection/GestureSelectionHelperTest.java
deleted file mode 100644
index 144fa7aa6..000000000
--- a/tests/unit/com/android/documentsui/selection/GestureSelectionHelperTest.java
+++ /dev/null
@@ -1,159 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-
-import androidx.recyclerview.widget.RecyclerView;
-
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.testing.SelectionProbe;
-import com.android.documentsui.selection.testing.TestData;
-import com.android.documentsui.testing.SelectionHelpers;
-import com.android.documentsui.testing.TestEvents;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.List;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class GestureSelectionHelperTest {
-
-    private static final List<String> ITEMS = TestData.create(100);
-    private static final MotionEvent DOWN = TestEvents.builder()
-            .action(MotionEvent.ACTION_DOWN)
-            .location(1, 1)
-            .build();
-
-    private static final MotionEvent MOVE = TestEvents.builder()
-            .action(MotionEvent.ACTION_MOVE)
-            .location(1, 1)
-            .build();
-
-    private static final MotionEvent UP = TestEvents.builder()
-            .action(MotionEvent.ACTION_UP)
-            .location(1, 1)
-            .build();
-
-    private GestureSelectionHelper mHelper;
-    private SelectionHelper mSelectionHelper;
-    private SelectionProbe mSelection;
-    private ContentLock mLock;
-    private TestItemDetailsLookup mItemLookup;
-    private TestViewDelegate mView;
-
-    @Before
-    public void setUp() {
-        mSelectionHelper = SelectionHelpers.createTestInstance(ITEMS);
-        mSelection = new SelectionProbe(mSelectionHelper);
-        mLock = new ContentLock();
-        mItemLookup = new TestItemDetailsLookup();
-        mItemLookup.initAt(3);
-        mView = new TestViewDelegate();
-        mHelper = new GestureSelectionHelper(mSelectionHelper, mView, mLock, mItemLookup);
-    }
-
-    @Test
-    public void testIgnoresDown_NoPosition() {
-        mView.mNextPosition = RecyclerView.NO_POSITION;
-        assertFalse(mHelper.onInterceptTouchEvent(null, DOWN));
-    }
-
-    @Test
-    public void testIgnoresDown_NoItemDetails() {
-        mItemLookup.reset();
-        assertFalse(mHelper.onInterceptTouchEvent(null, DOWN));
-    }
-
-    @Test
-    public void testNoStartOnIllegalPosition() {
-        mView.mNextPosition = -1;
-        mHelper.onInterceptTouchEvent(null, DOWN);
-        mHelper.start();
-        assertFalse(mLock.isLocked());
-    }
-
-    @Test
-    public void testDoesNotClaimDownOnItem() {
-        mView.mNextPosition = 0;
-        assertFalse(mHelper.onInterceptTouchEvent(null, DOWN));
-    }
-
-    @Test
-    public void testClaimsMoveIfStarted() {
-        mView.mNextPosition = 0;
-        // TODO(b/109808552): This should be removed with that bug is fixed because it will be a
-        // no-op at that time.
-        mHelper.onInterceptTouchEvent(null, DOWN);
-
-        // Normally, this is controller by the TouchSelectionHelper via a a long press gesture.
-        mSelectionHelper.select("1");
-        mSelectionHelper.anchorRange(1);
-        mHelper.start();
-        assertTrue(mHelper.onInterceptTouchEvent(null, MOVE));
-    }
-
-    @Test
-    public void testCreatesRangeSelection() {
-        mView.mNextPosition = 1;
-        mHelper.onInterceptTouchEvent(null, DOWN);
-        // Another way we are implicitly coupled to TouchInputHandler, is that we depend on
-        // long press to establish the initial anchor point. Without that we'll get an
-        // error when we try to extend the range.
-
-        mSelectionHelper.select("1");
-        mSelectionHelper.anchorRange(1);
-        mHelper.start();
-
-        mHelper.onTouchEvent(null, MOVE);
-
-        mView.mNextPosition = 9;
-        mHelper.onTouchEvent(null, MOVE);
-        mHelper.onTouchEvent(null, UP);
-
-        mSelection.assertRangeSelected(1, 9);
-    }
-
-    private static final class TestViewDelegate extends GestureSelectionHelper.ViewDelegate {
-
-        private int mNextPosition = RecyclerView.NO_POSITION;
-
-        @Override
-        int getHeight() {
-            return 1000;
-        }
-
-        @Override
-        int getItemUnder(MotionEvent e) {
-            return mNextPosition;
-        }
-
-        @Override
-        int getLastGlidedItemPosition(MotionEvent e) {
-            return mNextPosition;
-        }
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/GestureSelectionHelper_RecyclerViewDelegateTest.java b/tests/unit/com/android/documentsui/selection/GestureSelectionHelper_RecyclerViewDelegateTest.java
deleted file mode 100644
index 9e05d0c50..000000000
--- a/tests/unit/com/android/documentsui/selection/GestureSelectionHelper_RecyclerViewDelegateTest.java
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import android.view.MotionEvent;
-import android.view.View;
-
-import com.android.documentsui.selection.GestureSelectionHelper.RecyclerViewDelegate;
-import com.android.documentsui.testing.TestEvents;
-
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class GestureSelectionHelper_RecyclerViewDelegateTest {
-
-    // Simulate a (20, 20) box locating at (20, 20)
-    static final int LEFT_BORDER = 20;
-    static final int RIGHT_BORDER = 40;
-    static final int TOP_BORDER = 20;
-    static final int BOTTOM_BORDER = 40;
-
-    @Test
-    public void testLtrPastLastItem() {
-        MotionEvent event = createEvent(100, 100);
-        assertTrue(RecyclerViewDelegate.isPastLastItem(
-                TOP_BORDER, LEFT_BORDER, RIGHT_BORDER, event, View.LAYOUT_DIRECTION_LTR));
-    }
-
-    @Test
-    public void testLtrPastLastItem_Inverse() {
-        MotionEvent event = createEvent(10, 10);
-        assertFalse(RecyclerViewDelegate.isPastLastItem(
-                TOP_BORDER, LEFT_BORDER, RIGHT_BORDER, event, View.LAYOUT_DIRECTION_LTR));
-    }
-
-    @Test
-    public void testRtlPastLastItem() {
-        MotionEvent event = createEvent(10, 30);
-        assertTrue(RecyclerViewDelegate.isPastLastItem(
-                TOP_BORDER, LEFT_BORDER, RIGHT_BORDER, event, View.LAYOUT_DIRECTION_RTL));
-    }
-
-    @Test
-    public void testRtlPastLastItem_Inverse() {
-        MotionEvent event = createEvent(100, 100);
-        assertFalse(RecyclerViewDelegate.isPastLastItem(
-                TOP_BORDER, LEFT_BORDER, RIGHT_BORDER, event, View.LAYOUT_DIRECTION_RTL));
-    }
-
-    private static MotionEvent createEvent(int x, int y) {
-        return TestEvents.builder().action(MotionEvent.ACTION_MOVE).location(x, y).build();
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/GridModelTest.java b/tests/unit/com/android/documentsui/selection/GridModelTest.java
deleted file mode 100644
index 9b1523561..000000000
--- a/tests/unit/com/android/documentsui/selection/GridModelTest.java
+++ /dev/null
@@ -1,493 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static com.android.documentsui.selection.GridModel.NOT_SET;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import android.graphics.Point;
-import android.graphics.Rect;
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import androidx.recyclerview.widget.RecyclerView.OnScrollListener;
-
-import com.android.documentsui.selection.BandSelectionHelper.BandHost;
-import com.android.documentsui.selection.testing.SelectionPredicates;
-import com.android.documentsui.selection.testing.TestAdapter;
-import com.android.documentsui.selection.testing.TestStableIdProvider;
-
-import org.junit.After;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Set;
-
-import javax.annotation.Nullable;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class GridModelTest {
-
-    private static final int VIEW_PADDING_PX = 5;
-    private static final int CHILD_VIEW_EDGE_PX = 100;
-    private static final int VIEWPORT_HEIGHT = 500;
-
-    private GridModel mModel;
-    private TestHost mHost;
-    private TestAdapter mAdapter;
-    private Set<String> mLastSelection;
-    private int mViewWidth;
-
-    // TLDR: Don't call model.{start|resize}Selection; use the local #startSelection and
-    // #resizeSelection methods instead.
-    //
-    // The reason for this is that selection is stateful and involves operations that take the
-    // current UI state (e.g scrolling) into account. This test maintains its own copy of the
-    // selection bounds as control data for verifying selections. Keep this data in sync by calling
-    // #startSelection and
-    // #resizeSelection.
-    private Point mSelectionOrigin;
-    private Point mSelectionPoint;
-
-    @After
-    public void tearDown() {
-        mModel = null;
-        mHost = null;
-        mLastSelection = null;
-    }
-
-    @Test
-    public void testSelectionLeftOfItems() {
-        initData(20, 5);
-        startSelection(new Point(0, 10));
-        resizeSelection(new Point(1, 11));
-        assertNoSelection();
-        assertEquals(NOT_SET, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testSelectionRightOfItems() {
-        initData(20, 4);
-        startSelection(new Point(mViewWidth - 1, 10));
-        resizeSelection(new Point(mViewWidth - 2, 11));
-        assertNoSelection();
-        assertEquals(NOT_SET, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testSelectionAboveItems() {
-        initData(20, 4);
-        startSelection(new Point(10, 0));
-        resizeSelection(new Point(11, 1));
-        assertNoSelection();
-        assertEquals(NOT_SET, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testSelectionBelowItems() {
-        initData(5, 4);
-        startSelection(new Point(10, VIEWPORT_HEIGHT - 1));
-        resizeSelection(new Point(11, VIEWPORT_HEIGHT - 2));
-        assertNoSelection();
-        assertEquals(NOT_SET, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testVerticalSelectionBetweenItems() {
-        initData(20, 4);
-        startSelection(new Point(106, 0));
-        resizeSelection(new Point(107, 200));
-        assertNoSelection();
-        assertEquals(NOT_SET, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testHorizontalSelectionBetweenItems() {
-        initData(20, 4);
-        startSelection(new Point(0, 105));
-        resizeSelection(new Point(200, 106));
-        assertNoSelection();
-        assertEquals(NOT_SET, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testGrowingAndShrinkingSelection() {
-        initData(20, 4);
-        startSelection(new Point(0, 0));
-
-        resizeSelection(new Point(5, 5));
-        verifySelection();
-
-        resizeSelection(new Point(109, 109));
-        verifySelection();
-
-        resizeSelection(new Point(110, 109));
-        verifySelection();
-
-        resizeSelection(new Point(110, 110));
-        verifySelection();
-
-        resizeSelection(new Point(214, 214));
-        verifySelection();
-
-        resizeSelection(new Point(215, 214));
-        verifySelection();
-
-        resizeSelection(new Point(214, 214));
-        verifySelection();
-
-        resizeSelection(new Point(110, 110));
-        verifySelection();
-
-        resizeSelection(new Point(110, 109));
-        verifySelection();
-
-        resizeSelection(new Point(109, 109));
-        verifySelection();
-
-        resizeSelection(new Point(5, 5));
-        verifySelection();
-
-        resizeSelection(new Point(0, 0));
-        verifySelection();
-
-        assertEquals(NOT_SET, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testSelectionMovingAroundOrigin() {
-        initData(16, 4);
-
-        startSelection(new Point(210, 210));
-        resizeSelection(new Point(mViewWidth - 1, 0));
-        verifySelection();
-
-        resizeSelection(new Point(0, 0));
-        verifySelection();
-
-        resizeSelection(new Point(0, 420));
-        verifySelection();
-
-        resizeSelection(new Point(mViewWidth - 1, 420));
-        verifySelection();
-
-        // This is manually figured and will need to be adjusted if the separator position is
-        // changed.
-        assertEquals(7, mModel.getPositionNearestOrigin());
-    }
-
-    @Test
-    public void testScrollingBandSelect() {
-        initData(40, 4);
-
-        startSelection(new Point(0, 0));
-        resizeSelection(new Point(100, VIEWPORT_HEIGHT - 1));
-        verifySelection();
-
-        scroll(CHILD_VIEW_EDGE_PX);
-        verifySelection();
-
-        resizeSelection(new Point(200, VIEWPORT_HEIGHT - 1));
-        verifySelection();
-
-        scroll(CHILD_VIEW_EDGE_PX);
-        verifySelection();
-
-        scroll(-2 * CHILD_VIEW_EDGE_PX);
-        verifySelection();
-
-        resizeSelection(new Point(100, VIEWPORT_HEIGHT - 1));
-        verifySelection();
-
-        assertEquals(0, mModel.getPositionNearestOrigin());
-    }
-
-    private void initData(final int numChildren, int numColumns) {
-        mHost = new TestHost(numChildren, numColumns);
-        mAdapter = new TestAdapter() {
-            @Override
-            public String getStableId(int position) {
-                return Integer.toString(position);
-            }
-
-            @Override
-            public int getItemCount() {
-                return numChildren;
-            }
-        };
-
-        mViewWidth = VIEW_PADDING_PX + numColumns * (VIEW_PADDING_PX + CHILD_VIEW_EDGE_PX);
-
-        mModel = new GridModel(
-                mHost,
-                new TestStableIdProvider(mAdapter),
-                SelectionPredicates.CAN_SET_ANYTHING);
-
-        mModel.addOnSelectionChangedListener(
-                new GridModel.SelectionObserver() {
-                    @Override
-                    public void onSelectionChanged(Set<String> updatedSelection) {
-                        mLastSelection = updatedSelection;
-                    }
-                });
-    }
-
-    /** Returns the current selection area as a Rect. */
-    private Rect getSelectionArea() {
-        // Construct a rect from the two selection points.
-        Rect selectionArea = new Rect(
-                mSelectionOrigin.x, mSelectionOrigin.y, mSelectionOrigin.x, mSelectionOrigin.y);
-        selectionArea.union(mSelectionPoint.x, mSelectionPoint.y);
-        // Rect intersection tests are exclusive of bounds, while the MSM's selection code is
-        // inclusive. Expand the rect by 1 pixel in all directions to account for this.
-        selectionArea.inset(-1, -1);
-
-        return selectionArea;
-    }
-
-    /** Asserts that the selection is currently empty. */
-    private void assertNoSelection() {
-        assertEquals("Unexpected items " + mLastSelection + " in selection " + getSelectionArea(),
-                0, mLastSelection.size());
-    }
-
-    /** Verifies the selection using actual bbox checks. */
-    private void verifySelection() {
-        Rect selectionArea = getSelectionArea();
-        for (TestHost.Item item: mHost.items) {
-            if (Rect.intersects(selectionArea, item.rect)) {
-                assertTrue("Expected item " + item + " was not in selection " + selectionArea,
-                        mLastSelection.contains(item.name));
-            } else {
-                assertFalse("Unexpected item " + item + " in selection" + selectionArea,
-                        mLastSelection.contains(item.name));
-            }
-        }
-    }
-
-    private void startSelection(Point p) {
-        mModel.startCapturing(p);
-        mSelectionOrigin = mHost.createAbsolutePoint(p);
-    }
-
-    private void resizeSelection(Point p) {
-        mModel.resizeSelection(p);
-        mSelectionPoint = mHost.createAbsolutePoint(p);
-    }
-
-    private void scroll(int dy) {
-        assertTrue(mHost.verticalOffset + VIEWPORT_HEIGHT + dy <= mHost.getTotalHeight());
-        mHost.verticalOffset += dy;
-        // Correct the cached selection point as well.
-        mSelectionPoint.y += dy;
-        mHost.mScrollListener.onScrolled(null, 0, dy);
-    }
-
-    private static final class TestHost extends BandHost {
-
-        private final int mNumColumns;
-        private final int mNumRows;
-        private final int mNumChildren;
-        private final int mSeparatorPosition;
-
-        public int horizontalOffset = 0;
-        public int verticalOffset = 0;
-        private List<Item> items = new ArrayList<>();
-
-        // Installed by GridModel on construction.
-        private @Nullable OnScrollListener mScrollListener;
-
-        public TestHost(int numChildren, int numColumns) {
-            mNumChildren = numChildren;
-            mNumColumns = numColumns;
-            mSeparatorPosition = mNumColumns + 1;
-            mNumRows = setupGrid();
-        }
-
-        private int setupGrid() {
-            // Split the input set into folders and documents. Do this such that there is a
-            // partially-populated row in the middle of the grid, to test corner cases in layout
-            // code.
-            int y = VIEW_PADDING_PX;
-            int i = 0;
-            int numRows = 0;
-            while (i < mNumChildren) {
-                int top = y;
-                int height = CHILD_VIEW_EDGE_PX;
-                int width = CHILD_VIEW_EDGE_PX;
-                for (int j = 0; j < mNumColumns && i < mNumChildren; j++) {
-                    int left = VIEW_PADDING_PX + (j * (width + VIEW_PADDING_PX));
-                    items.add(new Item(
-                            Integer.toString(i),
-                            new Rect(
-                                    left,
-                                    top,
-                                    left + width - 1,
-                                    top + height - 1)));
-
-                    // Create a partially populated row at the separator position.
-                    if (++i == mSeparatorPosition) {
-                        break;
-                    }
-                }
-                y += height + VIEW_PADDING_PX;
-                numRows++;
-            }
-
-            return numRows;
-        }
-
-        private int getTotalHeight() {
-            return CHILD_VIEW_EDGE_PX * mNumRows + VIEW_PADDING_PX * (mNumRows + 1);
-        }
-
-        private int getFirstVisibleRowIndex() {
-            return verticalOffset / (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);
-        }
-
-        private int getLastVisibleRowIndex() {
-            int lastVisibleRowUncapped =
-                    (VIEWPORT_HEIGHT + verticalOffset - 1) / (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);
-            return Math.min(lastVisibleRowUncapped, mNumRows - 1);
-        }
-
-        private int getNumItemsInRow(int index) {
-            assertTrue(index >= 0 && index < mNumRows);
-            int mod = mSeparatorPosition % mNumColumns;
-            if (index == (mSeparatorPosition / mNumColumns)) {
-                // The row containing the separator may be incomplete
-                return mod > 0 ? mod : mNumColumns;
-            }
-            // Account for the partial separator row in the final row tally.
-            if (index == mNumRows - 1) {
-                // The last row may be incomplete
-                int finalRowCount = (mNumChildren - mod) % mNumColumns;
-                return finalRowCount > 0 ? finalRowCount : mNumColumns;
-            }
-
-            return mNumColumns;
-        }
-
-        @Override
-        public void addOnScrollListener(OnScrollListener listener) {
-            mScrollListener = listener;
-        }
-
-        @Override
-        public void removeOnScrollListener(OnScrollListener listener) {}
-
-        @Override
-        public Point createAbsolutePoint(Point relativePoint) {
-            return new Point(
-                    relativePoint.x + horizontalOffset, relativePoint.y + verticalOffset);
-        }
-
-        @Override
-        public int getVisibleChildCount() {
-            int childCount = 0;
-            for (int i = getFirstVisibleRowIndex(); i <= getLastVisibleRowIndex(); i++) {
-                childCount += getNumItemsInRow(i);
-            }
-            return childCount;
-        }
-
-        @Override
-        public int getAdapterPositionAt(int index) {
-            // Account for partial rows by actually tallying up the items in hidden rows.
-            int hiddenCount = 0;
-            for (int i = 0; i < getFirstVisibleRowIndex(); i++) {
-                hiddenCount += getNumItemsInRow(i);
-            }
-            return index + hiddenCount;
-        }
-
-        @Override
-        public Rect getAbsoluteRectForChildViewAt(int index) {
-            int adapterPosition = getAdapterPositionAt(index);
-            return items.get(adapterPosition).rect;
-        }
-
-        @Override
-        public int getChildCount() {
-            return mNumChildren;
-        }
-
-        @Override
-        public int getColumnCount() {
-            return mNumColumns;
-        }
-
-        @Override
-        public void showBand(Rect rect) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void hideBand() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void scrollBy(int dy) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public int getHeight() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void invalidateView() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void runAtNextFrame(Runnable r) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void removeCallback(Runnable r) {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public boolean hasView(int adapterPosition) {
-            return true;
-        }
-
-        public static final class Item {
-            public String name;
-            public Rect rect;
-
-            public Item(String n, Rect r) {
-                name = n;
-                rect = r;
-            }
-
-            @Override
-            public String toString() {
-                return name + ": " + rect;
-            }
-        }
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/MouseInputHandlerTest.java b/tests/unit/com/android/documentsui/selection/MouseInputHandlerTest.java
deleted file mode 100644
index c4d66d866..000000000
--- a/tests/unit/com/android/documentsui/selection/MouseInputHandlerTest.java
+++ /dev/null
@@ -1,285 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static com.android.documentsui.testing.TestEvents.Mouse.ALT_CLICK;
-import static com.android.documentsui.testing.TestEvents.Mouse.CLICK;
-import static com.android.documentsui.testing.TestEvents.Mouse.CTRL_CLICK;
-import static com.android.documentsui.testing.TestEvents.Mouse.SECONDARY_CLICK;
-import static com.android.documentsui.testing.TestEvents.Mouse.SHIFT_CLICK;
-import static com.android.documentsui.testing.TestEvents.Mouse.TERTIARY_CLICK;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.testing.SelectionHelpers;
-import com.android.documentsui.selection.testing.SelectionProbe;
-import com.android.documentsui.selection.testing.TestData;
-import com.android.documentsui.selection.testing.TestEvents;
-import com.android.documentsui.selection.testing.TestMouseCallbacks;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.List;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public final class MouseInputHandlerTest {
-
-    private static final List<String> ITEMS = TestData.create(100);
-
-    private MouseInputHandler mInputDelegate;
-    private TestMouseCallbacks mCallbacks;
-    private TestItemDetailsLookup mDetailsLookup;
-    private SelectionProbe mSelection;
-    private SelectionHelper mSelectionMgr;
-
-    private TestEvents.Builder mEvent;
-
-    @Before
-    public void setUp() {
-
-        mSelectionMgr = SelectionHelpers.createTestInstance(ITEMS);
-        mDetailsLookup = new TestItemDetailsLookup();
-        mSelection = new SelectionProbe(mSelectionMgr);
-
-        mCallbacks = new TestMouseCallbacks();
-        mInputDelegate = new MouseInputHandler(mSelectionMgr, mDetailsLookup, mCallbacks);
-
-        mEvent = TestEvents.builder().mouse();
-        mDetailsLookup.initAt(RecyclerView.NO_POSITION);
-    }
-
-    @Test
-    public void testConfirmedClick_StartsSelection() {
-        mDetailsLookup.initAt(11).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mSelection.assertSelection(11);
-    }
-
-    @Test
-    public void testClickOnSelectRegion_AddsToSelection() {
-        mDetailsLookup.initAt(11).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(10).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapUp(CLICK);
-
-        mSelection.assertSelected(10, 11);
-    }
-
-    @Test
-    public void testClickOnIconOfSelectedItem_RemovesFromSelection() {
-        mDetailsLookup.initAt(8).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-        mSelection.assertSelected(8, 9, 10, 11);
-
-        mDetailsLookup.initAt(9);
-        mInputDelegate.onSingleTapUp(CLICK);
-        mSelection.assertSelected(8, 10, 11);
-    }
-
-    @Test
-    public void testRightClickDown_StartsContextMenu() {
-        mInputDelegate.onDown(SECONDARY_CLICK);
-
-        mCallbacks.assertLastEvent(SECONDARY_CLICK);
-    }
-
-    @Test
-    public void testAltClickDown_StartsContextMenu() {
-        mInputDelegate.onDown(ALT_CLICK);
-
-        mCallbacks.assertLastEvent(ALT_CLICK);
-    }
-
-    @Test
-    public void testScroll_shouldTrap() {
-        mDetailsLookup.initAt(0);
-        assertTrue(mInputDelegate.onScroll(
-                null,
-                mEvent.action(MotionEvent.ACTION_MOVE).primary().build(),
-                -1,
-                -1));
-    }
-
-    @Test
-    public void testScroll_NoTrapForTwoFinger() {
-        mDetailsLookup.initAt(0);
-        assertFalse(mInputDelegate.onScroll(
-                null,
-                mEvent.action(MotionEvent.ACTION_MOVE).build(),
-                -1,
-                -1));
-    }
-
-    @Test
-    public void testUnconfirmedCtrlClick_AddsToExistingSelection() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(CTRL_CLICK);
-
-        mSelection.assertSelection(7, 11);
-    }
-
-    @Test
-    public void testUnconfirmedShiftClick_ExtendsSelection() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertSelection(7, 8, 9, 10, 11);
-    }
-
-    @Test
-    public void testConfirmedShiftClick_ExtendsSelectionFromOriginFocus() {
-        TestItemDetails item = mDetailsLookup.initAt(7);
-        mCallbacks.focusItem(item);
-
-        // This is a hack-y test, since the real FocusManager would've set range begin itself.
-        mSelectionMgr.anchorRange(7);
-        mSelection.assertNoSelection();
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapConfirmed(SHIFT_CLICK);
-        mSelection.assertSelection(7, 8, 9, 10, 11);
-    }
-
-    @Test
-    public void testUnconfirmedShiftClick_RotatesAroundOrigin() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-        mSelection.assertSelection(7, 8, 9, 10, 11);
-
-        mDetailsLookup.initAt(5);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertSelection(5, 6, 7);
-        mSelection.assertNotSelected(8, 9, 10, 11);
-    }
-
-    @Test
-    public void testUnconfirmedShiftCtrlClick_Combination() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-        mSelection.assertSelection(7, 8, 9, 10, 11);
-
-        mDetailsLookup.initAt(5);
-        mInputDelegate.onSingleTapUp(CTRL_CLICK);
-
-        mSelection.assertSelection(5, 7, 8, 9, 10, 11);
-    }
-
-    @Test
-    public void testUnconfirmedShiftCtrlClick_ShiftTakesPriority() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(mEvent.ctrl().shift().build());
-
-        mSelection.assertSelection(7, 8, 9, 10, 11);
-    }
-
-    // TODO: Add testSpaceBar_Previews, but we need to set a system property
-    // to have a deterministic state.
-
-    @Test
-    public void testDoubleClick_Opens() {
-        TestItemDetails doc = mDetailsLookup.initAt(11);
-        mInputDelegate.onDoubleTap(CLICK);
-
-        mCallbacks.assertActivated(doc);
-    }
-
-    @Test
-    public void testMiddleClick_DoesNothing() {
-        mDetailsLookup.initAt(11).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(TERTIARY_CLICK);
-
-        mSelection.assertNoSelection();
-    }
-
-    @Test
-    public void testClickOff_ClearsSelection() {
-        mDetailsLookup.initAt(11).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(RecyclerView.NO_POSITION);
-        mInputDelegate.onSingleTapUp(CLICK);
-
-        mSelection.assertNoSelection();
-    }
-
-    @Test
-    public void testClick_Focuses() {
-        mDetailsLookup.initAt(11).setInItemSelectRegion(false);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mCallbacks.assertHasFocus(true);
-        mCallbacks.assertFocused("11");
-    }
-
-    @Test
-    public void testClickOff_ClearsFocus() {
-        mDetailsLookup.initAt(11).setInItemSelectRegion(false);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-        mCallbacks.assertHasFocus(true);
-
-        mDetailsLookup.initAt(RecyclerView.NO_POSITION);
-        mInputDelegate.onSingleTapUp(CLICK);
-        mCallbacks.assertHasFocus(false);
-    }
-
-    @Test
-    public void testClickOffSelection_RemovesSelectionAndFocuses() {
-        mDetailsLookup.initAt(1).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(5);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertSelection(1, 2, 3, 4, 5);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(CLICK);
-
-        mCallbacks.assertFocused("11");
-        mSelection.assertNoSelection();
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/MouseInputHandler_RangeTest.java b/tests/unit/com/android/documentsui/selection/MouseInputHandler_RangeTest.java
deleted file mode 100644
index 939e77892..000000000
--- a/tests/unit/com/android/documentsui/selection/MouseInputHandler_RangeTest.java
+++ /dev/null
@@ -1,187 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static com.android.documentsui.testing.TestEvents.Mouse.CLICK;
-import static com.android.documentsui.testing.TestEvents.Mouse.SECONDARY_CLICK;
-import static com.android.documentsui.testing.TestEvents.Mouse.SHIFT_CLICK;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.testing.SelectionHelpers;
-import com.android.documentsui.selection.testing.SelectionProbe;
-import com.android.documentsui.selection.testing.TestData;
-import com.android.documentsui.selection.testing.TestMouseCallbacks;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.List;
-
-/**
- * MouseInputDelegate / SelectHelper integration test covering the shared
- * responsibility of range selection.
- */
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public final class MouseInputHandler_RangeTest {
-
-    private static final List<String> ITEMS = TestData.create(100);
-
-    private MouseInputHandler mInputDelegate;
-    private SelectionHelper mSelectionMgr;
-    private SelectionProbe mSelection;
-    private TestMouseCallbacks mCallbacks;
-    private TestItemDetailsLookup mDetailsLookup;
-
-    @Before
-    public void setUp() {
-        mSelectionMgr = SelectionHelpers.createTestInstance(ITEMS);
-        mDetailsLookup = new TestItemDetailsLookup();
-        mSelection = new SelectionProbe(mSelectionMgr);
-
-        mCallbacks = new TestMouseCallbacks();
-        mInputDelegate = new MouseInputHandler(mSelectionMgr, mDetailsLookup, mCallbacks);
-    }
-
-    @Test
-    public void testExtendRange() {
-        // uni-click just focuses.
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertRangeSelection(7, 11);
-    }
-
-    @Test
-    public void testExtendRangeContinues() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mDetailsLookup.initAt(21);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertRangeSelection(7, 21);
-    }
-
-    @Test
-    public void testMultipleContiguousRanges() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        // click without shift sets a new range start point.
-        TestItemDetails item = mDetailsLookup.initAt(20);
-        mInputDelegate.onSingleTapUp(CLICK);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mCallbacks.focusItem(item);
-
-        mDetailsLookup.initAt(25);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-        mInputDelegate.onSingleTapConfirmed(SHIFT_CLICK);
-
-        mSelection.assertRangeNotSelected(7, 11);
-        mSelection.assertRangeSelected(20, 25);
-        mSelection.assertSelectionSize(6);
-    }
-
-    @Test
-    public void testReducesSelectionRange() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(17);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mDetailsLookup.initAt(10);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertRangeSelection(7, 10);
-    }
-
-    @Test
-    public void testReducesSelectionRange_Reverse() {
-        mDetailsLookup.initAt(17).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(7);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mDetailsLookup.initAt(14);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertRangeSelection(14, 17);
-    }
-
-    @Test
-    public void testExtendsRange_Reverse() {
-        mDetailsLookup.initAt(12).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(5);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertRangeSelection(5, 12);
-    }
-
-    @Test
-    public void testExtendsRange_ReversesAfterForwardClick() {
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapConfirmed(CLICK);
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mDetailsLookup.initAt(0);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertRangeSelection(0, 7);
-    }
-
-    @Test
-    public void testRightClickEstablishesRange() {
-
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onDown(SECONDARY_CLICK);
-        // This next method call simulates the behavior of the system event dispatch code.
-        // UserInputHandler depends on a specific sequence of events for internal
-        // state to remain valid. It's not an awesome arrangement, but it is currently
-        // necessary.
-        //
-        // See: UserInputHandler.MouseDelegate#mHandledOnDown;
-        mInputDelegate.onSingleTapUp(SECONDARY_CLICK);
-
-        mDetailsLookup.initAt(11);
-        // Now we can send a subsequent event that should extend selection.
-        mInputDelegate.onDown(SHIFT_CLICK);
-        mInputDelegate.onSingleTapUp(SHIFT_CLICK);
-
-        mSelection.assertRangeSelection(7, 11);
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/SelectionTest.java b/tests/unit/com/android/documentsui/selection/SelectionTest.java
deleted file mode 100644
index fcf525bba..000000000
--- a/tests/unit/com/android/documentsui/selection/SelectionTest.java
+++ /dev/null
@@ -1,200 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static junit.framework.Assert.assertEquals;
-import static junit.framework.Assert.assertFalse;
-import static junit.framework.Assert.assertTrue;
-
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-
-import com.google.common.collect.Sets;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.HashSet;
-import java.util.Set;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class SelectionTest {
-
-    private Selection selection;
-
-    private String[] ids = new String[]{
-            "foo",
-            "43",
-            "auth|id=@53di*/f3#d"
-    };
-
-    @Before
-    public void setUp() throws Exception {
-        selection = new Selection();
-        selection.add(ids[0]);
-        selection.add(ids[1]);
-        selection.add(ids[2]);
-    }
-
-    @Test
-    public void testAdd() {
-        // We added in setUp.
-        assertEquals(3, selection.size());
-        assertContains(ids[0]);
-        assertContains(ids[1]);
-        assertContains(ids[2]);
-    }
-
-    @Test
-    public void testRemove() {
-        selection.remove(ids[0]);
-        selection.remove(ids[2]);
-        assertEquals(1, selection.size());
-        assertContains(ids[1]);
-    }
-
-    @Test
-    public void testClear() {
-        selection.clear();
-        assertEquals(0, selection.size());
-    }
-
-    @Test
-    public void testIsEmpty() {
-        assertTrue(new Selection().isEmpty());
-        selection.clear();
-        assertTrue(selection.isEmpty());
-    }
-
-    @Test
-    public void testSize() {
-        Selection other = new Selection();
-        for (int i = 0; i < selection.size(); i++) {
-            other.add(ids[i]);
-        }
-        assertEquals(selection.size(), other.size());
-    }
-
-    @Test
-    public void testEqualsSelf() {
-        assertEquals(selection, selection);
-    }
-
-    @Test
-    public void testEqualsOther() {
-        Selection other = new Selection();
-        other.add(ids[0]);
-        other.add(ids[1]);
-        other.add(ids[2]);
-        assertEquals(selection, other);
-        assertEquals(selection.hashCode(), other.hashCode());
-    }
-
-    @Test
-    public void testEqualsCopy() {
-        Selection other = new Selection();
-        other.copyFrom(selection);
-        assertEquals(selection, other);
-        assertEquals(selection.hashCode(), other.hashCode());
-    }
-
-    @Test
-    public void testNotEquals() {
-        Selection other = new Selection();
-        other.add("foobar");
-        assertFalse(selection.equals(other));
-    }
-
-    @Test
-    public void testIntersection_empty0() {
-        Selection testSelection = new Selection();
-        testSelection.intersect(new HashSet<String>());
-        assertTrue(testSelection.isEmpty());
-    }
-
-    @Test
-    public void testIntersection_empty1() {
-        Selection testSelection = new Selection();
-        testSelection.intersect(Sets.newHashSet("foo"));
-        assertTrue(testSelection.isEmpty());
-    }
-
-    @Test
-    public void testIntersection_empty2() {
-        assertFalse(selection.isEmpty());
-        selection.intersect(new HashSet<String>());
-        assertTrue(selection.isEmpty());
-    }
-
-    @Test
-    public void testIntersection_exclusive() {
-        String[] ids0 = new String[]{"foo", "bar", "baz"};
-        String[] ids1 = new String[]{"0", "1", "2"};
-
-        Selection testSelection = new Selection();
-        testSelection.add(ids0[0]);
-        testSelection.add(ids0[1]);
-        testSelection.add(ids0[2]);
-
-        Set<String> set = Sets.newHashSet(ids1);
-        testSelection.intersect(set);
-
-        assertTrue(testSelection.isEmpty());
-    }
-
-    @Test
-    public void testIntersection_subset() {
-        String[] ids0 = new String[]{"foo", "bar", "baz"};
-        String[] ids1 = new String[]{"0", "baz", "1", "foo", "2"};
-
-        Selection testSelection = new Selection();
-        testSelection.add(ids0[0]);
-        testSelection.add(ids0[1]);
-        testSelection.add(ids0[2]);
-
-        testSelection.intersect(Sets.newHashSet(ids1));
-
-        assertTrue(testSelection.contains("foo"));
-        assertFalse(testSelection.contains("bar"));
-        assertTrue(testSelection.contains("baz"));
-    }
-
-    @Test
-    public void testIntersection_all() {
-        String[] ids0 = new String[]{"foo", "bar", "baz"};
-        String[] ids1 = new String[]{"0", "baz", "1", "foo", "2", "bar"};
-
-        Selection testSelection = new Selection();
-        testSelection.add(ids0[0]);
-        testSelection.add(ids0[1]);
-        testSelection.add(ids0[2]);
-
-        Selection control = new Selection();
-        control.copyFrom(testSelection);
-
-        testSelection.intersect(Sets.newHashSet(ids1));
-
-        assertTrue(testSelection.equals(control));
-    }
-
-    private void assertContains(String id) {
-        String err = String.format("Selection %s does not contain %s", selection, id);
-        assertTrue(err, selection.contains(id));
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/TouchInputHandlerTest.java b/tests/unit/com/android/documentsui/selection/TouchInputHandlerTest.java
deleted file mode 100644
index 919f42564..000000000
--- a/tests/unit/com/android/documentsui/selection/TouchInputHandlerTest.java
+++ /dev/null
@@ -1,223 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection;
-
-import static com.android.documentsui.testing.TestEvents.Touch.TAP;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import androidx.annotation.Nullable;
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-import com.android.documentsui.selection.TouchInputHandler.Callbacks;
-import com.android.documentsui.selection.testing.SelectionHelpers;
-import com.android.documentsui.selection.testing.SelectionProbe;
-import com.android.documentsui.selection.testing.TestData;
-import com.android.documentsui.selection.testing.TestSelectionPredicate;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.List;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public final class TouchInputHandlerTest {
-
-    private static final List<String> ITEMS = TestData.create(100);
-
-    private TouchInputHandler mInputDelegate;
-    private SelectionHelper mSelectionMgr;
-    private TestSelectionPredicate mSelectionPredicate;
-    private TestRunnable mGestureStarted;
-    private TestCallbacks mCallbacks;
-    private TestItemDetailsLookup mDetailsLookup;
-    private SelectionProbe mSelection;
-
-    @Before
-    public void setUp() {
-        mSelectionMgr = SelectionHelpers.createTestInstance(ITEMS);
-        mDetailsLookup = new TestItemDetailsLookup();
-        mSelectionPredicate = new TestSelectionPredicate();
-        mSelection = new SelectionProbe(mSelectionMgr);
-        mGestureStarted = new TestRunnable();
-        mCallbacks = new TestCallbacks();
-
-        mInputDelegate = new TouchInputHandler(
-                mSelectionMgr,
-                mDetailsLookup,
-                mSelectionPredicate,
-                mGestureStarted,
-                mCallbacks);
-    }
-
-    @Test
-    public void testTap_ActivatesWhenNoExistingSelection() {
-        ItemDetails doc = mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(TAP);
-
-        mCallbacks.assertActivated(doc);
-    }
-
-    @Test
-    public void testScroll_shouldNotBeTrapped() {
-        assertFalse(mInputDelegate.onScroll(null, TAP, -1, -1));
-    }
-
-    @Test
-    public void testLongPress_SelectsItem() {
-        mSelectionPredicate.setReturnValue(true);
-
-        mDetailsLookup.initAt(7);
-        mInputDelegate.onLongPress(TAP);
-
-        mSelection.assertSelection(7);
-    }
-
-    @Test
-    public void testLongPress_StartsGestureSelection() {
-        mSelectionPredicate.setReturnValue(true);
-
-        mDetailsLookup.initAt(7);
-        mInputDelegate.onLongPress(TAP);
-        mGestureStarted.assertRan();
-    }
-
-    @Test
-    public void testSelectHotspot_StartsSelectionMode() {
-        mSelectionPredicate.setReturnValue(true);
-
-        mDetailsLookup.initAt(7).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapUp(TAP);
-
-        mSelection.assertSelection(7);
-    }
-
-    @Test
-    public void testSelectionHotspot_UnselectsSelectedItem() {
-        mSelectionMgr.select("11");
-
-        mDetailsLookup.initAt(11).setInItemSelectRegion(true);
-        mInputDelegate.onSingleTapUp(TAP);
-
-        mSelection.assertNoSelection();
-    }
-
-    @Test
-    public void testStartsSelection_PerformsHapticFeedback() {
-        mSelectionPredicate.setReturnValue(true);
-
-        mDetailsLookup.initAt(7);
-        mInputDelegate.onLongPress(TAP);
-
-        mCallbacks.assertVibrated();
-    }
-
-    @Test
-    public void testLongPress_AddsToSelection() {
-        mSelectionPredicate.setReturnValue(true);
-
-        mDetailsLookup.initAt(7);
-        mInputDelegate.onLongPress(TAP);
-
-        mDetailsLookup.initAt(99);
-        mInputDelegate.onLongPress(TAP);
-
-        mDetailsLookup.initAt(13);
-        mInputDelegate.onLongPress(TAP);
-
-        mSelection.assertSelection(7, 13, 99);
-    }
-
-    @Test
-    public void testTap_UnselectsSelectedItem() {
-        mSelectionMgr.select("11");
-
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(TAP);
-
-        mSelection.assertNoSelection();
-    }
-
-    @Test
-    public void testTapOff_ClearsSelection() {
-        mSelectionMgr.select("7");
-        mDetailsLookup.initAt(7);
-
-        mInputDelegate.onLongPress(TAP);
-
-        mSelectionMgr.select("11");
-        mDetailsLookup.initAt(11);
-        mInputDelegate.onSingleTapUp(TAP);
-
-        mDetailsLookup.initAt(RecyclerView.NO_POSITION).setInItemSelectRegion(false);
-        mInputDelegate.onSingleTapUp(TAP);
-
-        mSelection.assertNoSelection();
-    }
-
-    private static final class TestCallbacks extends TouchInputHandler.Callbacks {
-
-        private @Nullable ItemDetails mActivated;
-        private boolean mVibrated;
-
-        @Override
-        public boolean onItemActivated(ItemDetails item, MotionEvent e) {
-            mActivated = item;
-            return false;
-        }
-
-        @Override
-        public boolean onDragInitiated(MotionEvent e) {
-            return false;
-        }
-
-        @Override
-        public void onPerformHapticFeedback() {
-            mVibrated = true;
-        }
-
-        private void assertActivated(ItemDetails expected) {
-            assertEquals(expected, mActivated);
-        }
-
-        private void assertVibrated() {
-            assertTrue(mVibrated);
-        }
-    }
-
-    private static final class TestRunnable implements Runnable {
-
-        private boolean mWasRun;
-
-        @Override
-        public void run() {
-            mWasRun = true;
-        }
-
-        void assertRan() {
-            assertTrue(mWasRun);
-        }
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/SelectionHelpers.java b/tests/unit/com/android/documentsui/selection/testing/SelectionHelpers.java
deleted file mode 100644
index 6bdd18a2c..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/SelectionHelpers.java
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection.testing;
-
-import com.android.documentsui.selection.DefaultSelectionHelper;
-import com.android.documentsui.selection.DefaultSelectionHelper.SelectionMode;
-import com.android.documentsui.selection.SelectionHelper;
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-
-import java.util.Collections;
-import java.util.List;
-
-public class SelectionHelpers {
-
-    public static final SelectionPredicate CAN_SET_ANYTHING = new SelectionPredicate() {
-        @Override
-        public boolean canSetStateForId(String id, boolean nextState) {
-            return true;
-        }
-
-        @Override
-        public boolean canSetStateAtPosition(int position, boolean nextState) {
-            return true;
-        }
-    };
-
-    private SelectionHelpers() {}
-
-    public static SelectionHelper createTestInstance() {
-        return createTestInstance(Collections.emptyList());
-    }
-
-    public static SelectionHelper createTestInstance(List<String> docs) {
-        return createTestInstance(docs, DefaultSelectionHelper.MODE_MULTIPLE);
-    }
-
-    public static SelectionHelper createTestInstance(
-            List<String> items, @SelectionMode int mode) {
-        return createTestInstance(new TestAdapter(items), mode, CAN_SET_ANYTHING);
-    }
-
-    public static SelectionHelper createTestInstance(
-            TestAdapter adapter, @SelectionMode int mode, SelectionPredicate selPredicate) {
-        return new DefaultSelectionHelper(
-                mode, adapter, new TestStableIdProvider(adapter), selPredicate);
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/SelectionPredicates.java b/tests/unit/com/android/documentsui/selection/testing/SelectionPredicates.java
deleted file mode 100644
index 020091922..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/SelectionPredicates.java
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.testing;
-
-import com.android.documentsui.selection.SelectionHelper.SelectionPredicate;
-
-/**
- * Test friendly {@link SelectionPredicate} instances.
- */
-public final class SelectionPredicates {
-
-    private SelectionPredicates() {}
-
-    public static final SelectionPredicate CAN_SET_ANYTHING = new SelectionPredicate() {
-        @Override
-        public boolean canSetStateForId(String id, boolean nextState) {
-            return true;
-        }
-
-        @Override
-        public boolean canSetStateAtPosition(int position, boolean nextState) {
-            return true;
-        }
-    };
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/SelectionProbe.java b/tests/unit/com/android/documentsui/selection/testing/SelectionProbe.java
deleted file mode 100644
index 4d5790bf0..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/SelectionProbe.java
+++ /dev/null
@@ -1,110 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection.testing;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import com.android.documentsui.selection.DefaultSelectionHelper;
-import com.android.documentsui.selection.Selection;
-import com.android.documentsui.selection.SelectionHelper;
-
-/**
- * Helper class for making assertions against the state of a {@link DefaultSelectionHelper} instance
- * and the consistency of states between {@link DefaultSelectionHelper} and
- * {@link DefaultSelectionHelper.ItemEventCallback}.
- */
-public final class SelectionProbe {
-
-    private final SelectionHelper mMgr;
-    private final TestSelectionObserver mSelectionListener;
-
-    public SelectionProbe(SelectionHelper mgr) {
-        mMgr = mgr;
-        mSelectionListener = new TestSelectionObserver();
-        mMgr.addObserver(mSelectionListener);
-    }
-
-    public SelectionProbe(SelectionHelper mgr, TestSelectionObserver selectionListener) {
-        mMgr = mgr;
-        mSelectionListener = selectionListener;
-    }
-
-    public void assertRangeSelected(int begin, int end) {
-        for (int i = begin; i <= end; i++) {
-            assertSelected(i);
-        }
-    }
-
-    public void assertRangeNotSelected(int begin, int end) {
-        for (int i = begin; i <= end; i++) {
-            assertNotSelected(i);
-        }
-    }
-
-    public void assertRangeSelection(int begin, int end) {
-        assertSelectionSize(end - begin + 1);
-        assertRangeSelected(begin, end);
-    }
-
-    public void assertSelectionSize(int expected) {
-        Selection selection = mMgr.getSelection();
-        assertEquals(selection.toString(), expected, selection.size());
-
-        mSelectionListener.assertSelectionSize(expected);
-    }
-
-    public void assertNoSelection() {
-        assertSelectionSize(0);
-
-        mSelectionListener.assertNoSelection();
-    }
-
-    public void assertSelection(int... ids) {
-        assertSelected(ids);
-        assertEquals(ids.length, mMgr.getSelection().size());
-
-        mSelectionListener.assertSelectionSize(ids.length);
-    }
-
-    public void assertSelected(int... ids) {
-        Selection sel = mMgr.getSelection();
-        for (int id : ids) {
-            String sid = String.valueOf(id);
-            assertTrue(sid + " is not in selection " + sel, sel.contains(sid));
-
-            mSelectionListener.assertSelected(sid);
-        }
-    }
-
-    public void assertNotSelected(int... ids) {
-        Selection sel = mMgr.getSelection();
-        for (int id : ids) {
-            String sid = String.valueOf(id);
-            assertFalse(sid + " is in selection " + sel, sel.contains(sid));
-
-            mSelectionListener.assertNotSelected(sid);
-        }
-    }
-
-    public void select(int...positions) {
-        for (int position : positions) {
-            mMgr.select(String.valueOf(position));
-        }
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestAdapter.java b/tests/unit/com/android/documentsui/selection/testing/TestAdapter.java
deleted file mode 100644
index 4a2d3e542..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestAdapter.java
+++ /dev/null
@@ -1,126 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.testing;
-
-import static org.junit.Assert.assertTrue;
-
-import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.Adapter;
-import androidx.recyclerview.widget.RecyclerView.AdapterDataObserver;
-import android.view.ViewGroup;
-
-import com.android.documentsui.selection.SelectionHelper;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-
-public class TestAdapter extends Adapter<TestHolder> {
-
-    private final List<String> mItems = new ArrayList<>();
-    private final List<Integer> mNotifiedOfSelection = new ArrayList<>();
-    private final AdapterDataObserver mAdapterObserver;
-
-    public TestAdapter() {
-        this(Collections.EMPTY_LIST);
-    }
-
-    public TestAdapter(List<String> items) {
-        mItems.addAll(items);
-        mAdapterObserver = new RecyclerView.AdapterDataObserver() {
-
-            @Override
-            public void onChanged() {
-            }
-
-            @Override
-            public void onItemRangeChanged(int startPosition, int itemCount, Object payload) {
-                if (SelectionHelper.SELECTION_CHANGED_MARKER.equals(payload)) {
-                    int last = startPosition + itemCount;
-                    for (int i = startPosition; i < last; i++) {
-                        mNotifiedOfSelection.add(i);
-                    }
-                }
-            }
-
-            @Override
-            public void onItemRangeInserted(int startPosition, int itemCount) {
-            }
-
-            @Override
-            public void onItemRangeRemoved(int startPosition, int itemCount) {
-            }
-
-            @Override
-            public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
-                throw new UnsupportedOperationException();
-            }
-        };
-
-        registerAdapterDataObserver(mAdapterObserver);
-    }
-
-    @Override
-    public TestHolder onCreateViewHolder(ViewGroup parent, int viewType) {
-        return new TestHolder(parent);
-    }
-
-    @Override
-    public void onBindViewHolder(TestHolder holder, int position) {
-        throw new UnsupportedOperationException();
-    }
-
-    @Override
-    public int getItemCount() {
-        return mItems.size();
-    }
-
-    public void updateTestModelIds(List<String> items) {
-        mItems.clear();
-        mItems.addAll(items);
-
-        notifyDataSetChanged();
-    }
-
-    public List<String> getStableIds() {
-        return mItems;
-    }
-
-    public int getPosition(String id) {
-        return mItems.indexOf(id);
-    }
-
-    public String getStableId(int position) {
-        return mItems.get(position);
-    }
-
-
-    public void resetSelectionNotifications() {
-        mNotifiedOfSelection.clear();
-    }
-
-    public void assertNotifiedOfSelectionChange(int position) {
-        assertTrue(mNotifiedOfSelection.contains(position));
-    }
-
-    public static List<String> createItemList(int num) {
-        List<String> items = new ArrayList<>(num);
-        for (int i = 0; i < num; ++i) {
-            items.add(Integer.toString(i));
-        }
-        return items;
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestBandPredicate.java b/tests/unit/com/android/documentsui/selection/testing/TestBandPredicate.java
deleted file mode 100644
index 2e901a013..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestBandPredicate.java
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.testing;
-
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.BandPredicate;
-
-public class TestBandPredicate extends BandPredicate {
-
-    private boolean mCanInitiate = true;
-
-    public void setCanInitiate(boolean canInitiate) {
-        mCanInitiate = canInitiate;
-    }
-
-    @Override
-    public boolean canInitiate(MotionEvent e) {
-        return mCanInitiate;
-    }
-
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestData.java b/tests/unit/com/android/documentsui/selection/testing/TestData.java
deleted file mode 100644
index 1a0599072..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestData.java
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection.testing;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class TestData {
-    public static List<String> create(int num) {
-        List<String> items = new ArrayList<String>(num);
-        for (int i = 0; i < num; ++i) {
-            items.add(Integer.toString(i));
-        }
-        return items;
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestEvents.java b/tests/unit/com/android/documentsui/selection/testing/TestEvents.java
deleted file mode 100644
index 828704ffc..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestEvents.java
+++ /dev/null
@@ -1,281 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection.testing;
-
-import androidx.annotation.IntDef;
-import android.graphics.Point;
-import android.view.KeyEvent;
-import android.view.MotionEvent;
-import android.view.MotionEvent.PointerCoords;
-import android.view.MotionEvent.PointerProperties;
-
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.util.HashSet;
-import java.util.Set;
-
-/**
- * Handy-dandy wrapper class to facilitate the creation of MotionEvents.
- */
-public final class TestEvents {
-
-    /**
-     * Common mouse event types...for your convenience.
-     */
-    public static final class Mouse {
-        public static final MotionEvent CLICK =
-                TestEvents.builder().mouse().primary().build();
-        public static final MotionEvent CTRL_CLICK =
-                TestEvents.builder().mouse().primary().ctrl().build();
-        public static final MotionEvent ALT_CLICK =
-                TestEvents.builder().mouse().primary().alt().build();
-        public static final MotionEvent SHIFT_CLICK =
-                TestEvents.builder().mouse().primary().shift().build();
-        public static final MotionEvent SECONDARY_CLICK =
-                TestEvents.builder().mouse().secondary().build();
-        public static final MotionEvent TERTIARY_CLICK =
-                TestEvents.builder().mouse().tertiary().build();
-    }
-
-    /**
-     * Common touch event types...for your convenience.
-     */
-    public static final class Touch {
-        public static final MotionEvent TAP =
-                TestEvents.builder().touch().build();
-    }
-
-    static final int ACTION_UNSET = -1;
-
-    // Add other actions from MotionEvent.ACTION_ as needed.
-    @IntDef(flag = true, value = {
-            MotionEvent.ACTION_DOWN,
-            MotionEvent.ACTION_MOVE,
-            MotionEvent.ACTION_UP
-    })
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface Action {}
-
-    // Add other types from MotionEvent.TOOL_TYPE_ as needed.
-    @IntDef(flag = true, value = {
-            MotionEvent.TOOL_TYPE_FINGER,
-            MotionEvent.TOOL_TYPE_MOUSE,
-            MotionEvent.TOOL_TYPE_STYLUS,
-            MotionEvent.TOOL_TYPE_UNKNOWN
-    })
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface ToolType {}
-
-    @IntDef(flag = true, value = {
-            MotionEvent.BUTTON_PRIMARY,
-            MotionEvent.BUTTON_SECONDARY
-    })
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface Button {}
-
-    @IntDef(flag = true, value = {
-            KeyEvent.META_SHIFT_ON,
-            KeyEvent.META_CTRL_ON
-    })
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface Key {}
-
-    private static final class State {
-        private @Action int mAction = ACTION_UNSET;
-        private @ToolType int mToolType = MotionEvent.TOOL_TYPE_UNKNOWN;
-        private int mPointerCount = 1;
-        private Set<Integer> mButtons = new HashSet<>();
-        private Set<Integer> mKeys = new HashSet<>();
-        private Point mLocation = new Point(0, 0);
-        private Point mRawLocation = new Point(0, 0);
-    }
-
-    public static final Builder builder() {
-        return new Builder();
-    }
-
-    /**
-     * Test event builder with convenience methods for common event attrs.
-     */
-    public static final class Builder {
-
-        private State mState = new State();
-
-        /**
-         * @param action Any action specified in {@link MotionEvent}.
-         * @return
-         */
-        public Builder action(int action) {
-            mState.mAction = action;
-            return this;
-        }
-
-        public Builder type(@ToolType int type) {
-            mState.mToolType = type;
-            return this;
-        }
-
-        public Builder location(int x, int y) {
-            mState.mLocation = new Point(x, y);
-            return this;
-        }
-
-        public Builder rawLocation(int x, int y) {
-            mState.mRawLocation = new Point(x, y);
-            return this;
-        }
-
-        public Builder pointerCount(int count) {
-            mState.mPointerCount = count;
-            return this;
-        }
-
-        /**
-         * Adds one or more button press attributes.
-         */
-        public Builder pressButton(@Button int... buttons) {
-            for (int button : buttons) {
-                mState.mButtons.add(button);
-            }
-            return this;
-        }
-
-        /**
-         * Removes one or more button press attributes.
-         */
-        public Builder releaseButton(@Button int... buttons) {
-            for (int button : buttons) {
-                mState.mButtons.remove(button);
-            }
-            return this;
-        }
-
-        /**
-         * Adds one or more key press attributes.
-         */
-        public Builder pressKey(@Key int... keys) {
-            for (int key : keys) {
-                mState.mKeys.add(key);
-            }
-            return this;
-        }
-
-        /**
-         * Removes one or more key press attributes.
-         */
-        public Builder releaseKey(@Button int... keys) {
-            for (int key : keys) {
-                mState.mKeys.remove(key);
-            }
-            return this;
-        }
-
-        public Builder touch() {
-            type(MotionEvent.TOOL_TYPE_FINGER);
-            return this;
-        }
-
-        public Builder mouse() {
-            type(MotionEvent.TOOL_TYPE_MOUSE);
-            return this;
-        }
-
-        public Builder shift() {
-            pressKey(KeyEvent.META_SHIFT_ON);
-            return this;
-        }
-
-        /**
-         * Use {@link #remove(@Attribute int...)}
-         */
-        public Builder unshift() {
-            releaseKey(KeyEvent.META_SHIFT_ON);
-            return this;
-        }
-
-        public Builder ctrl() {
-            pressKey(KeyEvent.META_CTRL_ON);
-            return this;
-        }
-
-        public Builder alt() {
-            pressKey(KeyEvent.META_ALT_ON);
-            return this;
-        }
-
-        public Builder primary() {
-            pressButton(MotionEvent.BUTTON_PRIMARY);
-            releaseButton(MotionEvent.BUTTON_SECONDARY);
-            releaseButton(MotionEvent.BUTTON_TERTIARY);
-            return this;
-        }
-
-        public Builder secondary() {
-            pressButton(MotionEvent.BUTTON_SECONDARY);
-            releaseButton(MotionEvent.BUTTON_PRIMARY);
-            releaseButton(MotionEvent.BUTTON_TERTIARY);
-            return this;
-        }
-
-        public Builder tertiary() {
-            pressButton(MotionEvent.BUTTON_TERTIARY);
-            releaseButton(MotionEvent.BUTTON_PRIMARY);
-            releaseButton(MotionEvent.BUTTON_SECONDARY);
-            return this;
-        }
-
-        public MotionEvent build() {
-
-            PointerProperties[] pointers = new PointerProperties[1];
-            pointers[0] = new PointerProperties();
-            pointers[0].id = 0;
-            pointers[0].toolType = mState.mToolType;
-
-            PointerCoords[] coords = new PointerCoords[1];
-            coords[0] = new PointerCoords();
-            coords[0].x = mState.mLocation.x;
-            coords[0].y = mState.mLocation.y;
-
-            int buttons = 0;
-            for (Integer button : mState.mButtons) {
-                buttons |= button;
-            }
-
-            int keys = 0;
-            for (Integer key : mState.mKeys) {
-                keys |= key;
-            }
-
-            return MotionEvent.obtain(
-                    0,     // down time
-                    1,     // event time
-                    mState.mAction,
-                    1,  // pointerCount,
-                    pointers,
-                    coords,
-                    keys,
-                    buttons,
-                    1.0f,  // x precision
-                    1.0f,  // y precision
-                    0,     // device id
-                    0,     // edge flags
-                    0,     // int source,
-                    0      // int flags
-                    );
-        }
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestHolder.java b/tests/unit/com/android/documentsui/selection/testing/TestHolder.java
deleted file mode 100644
index 071f808a3..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestHolder.java
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.testing;
-
-import androidx.recyclerview.widget.RecyclerView.ViewHolder;
-import android.view.View;
-
-public class TestHolder extends ViewHolder {
-    public TestHolder(View itemView) {
-        super(itemView);
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestMouseCallbacks.java b/tests/unit/com/android/documentsui/selection/testing/TestMouseCallbacks.java
deleted file mode 100644
index 32b5bfeef..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestMouseCallbacks.java
+++ /dev/null
@@ -1,88 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.testing;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.MotionEvent;
-
-import com.android.documentsui.selection.MouseInputHandler;
-import com.android.documentsui.selection.ItemDetailsLookup.ItemDetails;
-
-public final class TestMouseCallbacks extends MouseInputHandler.Callbacks {
-
-    private String mFocusItemId;
-    private int mFocusPosition;
-    private MotionEvent mLastContextEvent;
-    private ItemDetails mActivated;
-
-    @Override
-    public boolean onItemActivated(ItemDetails item, MotionEvent e) {
-        mActivated = item;
-        return true;
-    }
-
-    @Override
-    public boolean onContextClick(MotionEvent e) {
-        mLastContextEvent = e;
-        return false;
-    }
-
-    @Override
-    public void onPerformHapticFeedback() {
-    }
-
-    @Override
-    public void clearFocus() {
-        mFocusPosition = RecyclerView.NO_POSITION;
-        mFocusItemId = null;
-    }
-
-    @Override
-    public void focusItem(ItemDetails item) {
-        mFocusItemId = item.getStableId();
-        mFocusPosition = item.getPosition();
-    }
-
-    @Override
-    public int getFocusedPosition() {
-        return mFocusPosition;
-    }
-
-    @Override
-    public boolean hasFocusedItem() {
-        return mFocusItemId != null;
-    }
-
-    public void assertLastEvent(MotionEvent expected) {
-        // sadly, MotionEvent doesn't implement equals, so we compare references.
-        assertTrue(expected == mLastContextEvent);
-    }
-
-    public void assertActivated(ItemDetails expected) {
-        assertEquals(expected, mActivated);
-    }
-
-    public void assertHasFocus(boolean focused) {
-        assertEquals(focused, hasFocusedItem());
-    }
-
-    public void assertFocused(String expectedId) {
-        assertEquals(expectedId, mFocusItemId);
-    }
-}
\ No newline at end of file
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestSelectionObserver.java b/tests/unit/com/android/documentsui/selection/testing/TestSelectionObserver.java
deleted file mode 100644
index e75bde3de..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestSelectionObserver.java
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.documentsui.selection.testing;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import com.android.documentsui.selection.SelectionHelper.SelectionObserver;
-
-import java.util.HashSet;
-import java.util.Set;
-
-public class TestSelectionObserver extends SelectionObserver {
-
-    private final Set<String> mSelected = new HashSet<>();
-    private boolean mSelectionChanged = false;
-    private boolean mSelectionReset = false;
-    private boolean mSelectionRestored = false;
-
-    public void reset() {
-        mSelected.clear();
-        mSelectionChanged = false;
-        mSelectionReset = false;
-    }
-
-    @Override
-    public void onItemStateChanged(String id, boolean selected) {
-        if (selected) {
-            assertNotSelected(id);
-            mSelected.add(id);
-        } else {
-            assertSelected(id);
-            mSelected.remove(id);
-        }
-    }
-
-    @Override
-    public void onSelectionReset() {
-        mSelectionReset = true;
-        mSelected.clear();
-    }
-
-    @Override
-    public void onSelectionChanged() {
-        mSelectionChanged = true;
-    }
-
-    @Override
-    public void onSelectionRestored() {
-        mSelectionRestored = true;
-    }
-
-    void assertNoSelection() {
-        assertTrue(mSelected.isEmpty());
-    }
-
-    void assertSelectionSize(int expected) {
-        assertEquals(expected, mSelected.size());
-    }
-
-    void assertSelected(String id) {
-        assertTrue(id + " is not selected.", mSelected.contains(id));
-    }
-
-    void assertNotSelected(String id) {
-        assertFalse(id + " is already selected", mSelected.contains(id));
-    }
-
-    public void assertSelectionChanged() {
-        assertTrue(mSelectionChanged);
-    }
-
-    public void assertSelectionUnchanged() {
-        assertFalse(mSelectionChanged);
-    }
-
-    public void assertSelectionReset() {
-        assertTrue(mSelectionReset);
-    }
-
-    public void assertSelectionRestored() {
-        assertTrue(mSelectionRestored);
-    }
-}
diff --git a/tests/unit/com/android/documentsui/selection/testing/TestStableIdProvider.java b/tests/unit/com/android/documentsui/selection/testing/TestStableIdProvider.java
deleted file mode 100644
index 37c4665c8..000000000
--- a/tests/unit/com/android/documentsui/selection/testing/TestStableIdProvider.java
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.documentsui.selection.testing;
-
-import static androidx.core.util.Preconditions.checkArgument;
-
-import com.android.documentsui.selection.SelectionHelper.StableIdProvider;
-
-import java.util.List;
-
-/**
- * Provides RecyclerView selection code access to stable ids backed
- * by TestAdapter.
- */
-public final class TestStableIdProvider extends StableIdProvider {
-
-    private final TestAdapter mAdapter;
-
-    public TestStableIdProvider(TestAdapter adapter) {
-        checkArgument(adapter != null);
-        mAdapter = adapter;
-    }
-
-    @Override
-    public String getStableId(int position) {
-        return mAdapter.getStableId(position);
-    }
-
-    @Override
-    public int getPosition(String id) {
-        return mAdapter.getPosition(id);
-    }
-
-    @Override
-    public List<String> getStableIds() {
-        return mAdapter.getStableIds();
-    }
-}