Merge "Rename WindowDecorModelView to reflect purposes" into tm-qpr-dev am: 9fcbcb0762

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20534843

Change-Id: Iae39084cfb0cbd5102d116e5df6f28bb96511871
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

8 files changed, 408 insertions, 86 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java b/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java
index 90b35a5a55e1..44bcdb2d5de5 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskListener.java
@@ -82,7 +82,7 @@ public class FreeformTaskListener implements ShellTaskOrganizer.TaskListener {
         mTasks.put(taskInfo.taskId, state);
         if (!Transitions.ENABLE_SHELL_TRANSITIONS) {
             SurfaceControl.Transaction t = new SurfaceControl.Transaction();
-            mWindowDecorationViewModel.createWindowDecoration(taskInfo, leash, t, t);
+            mWindowDecorationViewModel.onTaskOpening(taskInfo, leash, t, t);
             t.apply();
         }
 
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserver.java b/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserver.java
index 168f6d79a390..6e710f7caeda 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserver.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserver.java
@@ -120,7 +120,7 @@ public class FreeformTaskTransitionObserver implements Transitions.TransitionObs
             TransitionInfo.Change change,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
-        mWindowDecorViewModel.createWindowDecoration(
+        mWindowDecorViewModel.onTaskOpening(
                 change.getTaskInfo(), change.getLeash(), startT, finishT);
     }
 
@@ -128,31 +128,23 @@ public class FreeformTaskTransitionObserver implements Transitions.TransitionObs
             TransitionInfo.Change change,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
-        mWindowDecorViewModel.setupWindowDecorationForTransition(
-                change.getTaskInfo(), startT, finishT);
+        mWindowDecorViewModel.onTaskClosing(change.getTaskInfo(), startT, finishT);
     }
 
     private void onChangeTransitionReady(
             TransitionInfo.Change change,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
-        mWindowDecorViewModel.setupWindowDecorationForTransition(
-                change.getTaskInfo(), startT, finishT);
+        mWindowDecorViewModel.onTaskChanging(
+                change.getTaskInfo(), change.getLeash(), startT, finishT);
     }
 
     private void onToFrontTransitionReady(
             TransitionInfo.Change change,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
-        boolean exists = mWindowDecorViewModel.setupWindowDecorationForTransition(
-                change.getTaskInfo(),
-                startT,
-                finishT);
-        if (!exists) {
-            // Window caption does not exist, create it
-            mWindowDecorViewModel.createWindowDecoration(
-                    change.getTaskInfo(), change.getLeash(), startT, finishT);
-        }
+        mWindowDecorViewModel.onTaskChanging(
+                change.getTaskInfo(), change.getLeash(), startT, finishT);
     }
 
     @Override
@@ -188,4 +180,4 @@ public class FreeformTaskTransitionObserver implements Transitions.TransitionObs
             mWindowDecorViewModel.destroyWindowDecoration(taskInfo.get(i));
         }
     }
-}
+}
\ No newline at end of file
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/fullscreen/FullscreenTaskListener.java b/libs/WindowManager/Shell/src/com/android/wm/shell/fullscreen/FullscreenTaskListener.java
index 75a4091c7d78..6623f5ca84ee 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/fullscreen/FullscreenTaskListener.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/fullscreen/FullscreenTaskListener.java
@@ -103,7 +103,7 @@ public class FullscreenTaskListener implements ShellTaskOrganizer.TaskListener {
         if (mWindowDecorViewModelOptional.isPresent()) {
             SurfaceControl.Transaction t = new SurfaceControl.Transaction();
             createdWindowDecor = mWindowDecorViewModelOptional.get()
-                    .createWindowDecoration(taskInfo, leash, t, t);
+                    .onTaskOpening(taskInfo, leash, t, t);
             t.apply();
         }
         if (!createdWindowDecor) {
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
index 8369569b4163..e40db4e4dcf2 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
@@ -55,6 +55,8 @@ import com.android.wm.shell.desktopmode.DesktopModeStatus;
 import com.android.wm.shell.freeform.FreeformTaskTransitionStarter;
 import com.android.wm.shell.transition.Transitions;
 
+import java.util.function.Supplier;
+
 /**
  * View model for the window decoration with a caption and shadows. Works with
  * {@link CaptionWindowDecoration}.
@@ -62,6 +64,8 @@ import com.android.wm.shell.transition.Transitions;
 
 public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
     private static final String TAG = "CaptionViewModel";
+    private final CaptionWindowDecoration.Factory mCaptionWindowDecorFactory;
+    private final Supplier<InputManager> mInputManagerSupplier;
     private final ActivityTaskManager mActivityTaskManager;
     private final ShellTaskOrganizer mTaskOrganizer;
     private final Context mContext;
@@ -77,6 +81,7 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
 
     private final SparseArray<CaptionWindowDecoration> mWindowDecorByTaskId = new SparseArray<>();
     private final DragStartListenerImpl mDragStartListener = new DragStartListenerImpl();
+    private EventReceiverFactory mEventReceiverFactory = new EventReceiverFactory();
 
     public CaptionWindowDecorViewModel(
             Context context,
@@ -86,6 +91,29 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
             DisplayController displayController,
             SyncTransactionQueue syncQueue,
             DesktopModeController desktopModeController) {
+        this(
+                context,
+                mainHandler,
+                mainChoreographer,
+                taskOrganizer,
+                displayController,
+                syncQueue,
+                desktopModeController,
+                new CaptionWindowDecoration.Factory(),
+                InputManager::getInstance);
+    }
+
+    public CaptionWindowDecorViewModel(
+            Context context,
+            Handler mainHandler,
+            Choreographer mainChoreographer,
+            ShellTaskOrganizer taskOrganizer,
+            DisplayController displayController,
+            SyncTransactionQueue syncQueue,
+            DesktopModeController desktopModeController,
+            CaptionWindowDecoration.Factory captionWindowDecorFactory,
+            Supplier<InputManager> inputManagerSupplier) {
+
         mContext = context;
         mMainHandler = mainHandler;
         mMainChoreographer = mainChoreographer;
@@ -94,7 +122,13 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
         mDisplayController = displayController;
         mSyncQueue = syncQueue;
         mDesktopModeController = desktopModeController;
-        mTransitionDragActive = false;
+
+        mCaptionWindowDecorFactory = captionWindowDecorFactory;
+        mInputManagerSupplier = inputManagerSupplier;
+    }
+
+    void setEventReceiverFactory(EventReceiverFactory eventReceiverFactory) {
+        mEventReceiverFactory = eventReceiverFactory;
     }
 
     @Override
@@ -103,42 +137,13 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
     }
 
     @Override
-    public boolean createWindowDecoration(
+    public boolean onTaskOpening(
             ActivityManager.RunningTaskInfo taskInfo,
             SurfaceControl taskSurface,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
         if (!shouldShowWindowDecor(taskInfo)) return false;
-        CaptionWindowDecoration oldDecoration = mWindowDecorByTaskId.get(taskInfo.taskId);
-        if (oldDecoration != null) {
-            // close the old decoration if it exists to avoid two window decorations being added
-            oldDecoration.close();
-        }
-        final CaptionWindowDecoration windowDecoration = new CaptionWindowDecoration(
-                mContext,
-                mDisplayController,
-                mTaskOrganizer,
-                taskInfo,
-                taskSurface,
-                mMainHandler,
-                mMainChoreographer,
-                mSyncQueue);
-        mWindowDecorByTaskId.put(taskInfo.taskId, windowDecoration);
-
-        TaskPositioner taskPositioner = new TaskPositioner(mTaskOrganizer, windowDecoration,
-                mDragStartListener);
-        CaptionTouchEventListener touchEventListener =
-                new CaptionTouchEventListener(taskInfo, taskPositioner,
-                        windowDecoration.getDragDetector());
-        windowDecoration.setCaptionListeners(touchEventListener, touchEventListener);
-        windowDecoration.setDragResizeCallback(taskPositioner);
-        setupWindowDecorationForTransition(taskInfo, startT, finishT);
-        if (mInputMonitor == null) {
-            mInputMonitor = InputManager.getInstance().monitorGestureInput(
-                    "caption-touch", mContext.getDisplayId());
-            mEventReceiver = new EventReceiver(
-                    mInputMonitor.getInputChannel(), Looper.myLooper());
-        }
+        createWindowDecoration(taskInfo, taskSurface, startT, finishT);
         return true;
     }
 
@@ -151,25 +156,45 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
     }
 
     @Override
-    public boolean setupWindowDecorationForTransition(
+    public void onTaskChanging(
+            RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        final CaptionWindowDecoration decoration = mWindowDecorByTaskId.get(taskInfo.taskId);
+
+        if (!shouldShowWindowDecor(taskInfo)) {
+            if (decoration != null) {
+                destroyWindowDecoration(taskInfo);
+            }
+            return;
+        }
+
+        if (decoration == null) {
+            createWindowDecoration(taskInfo, taskSurface, startT, finishT);
+        } else {
+            decoration.relayout(taskInfo, startT, finishT);
+        }
+    }
+
+    @Override
+    public void onTaskClosing(
             RunningTaskInfo taskInfo,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
         final CaptionWindowDecoration decoration = mWindowDecorByTaskId.get(taskInfo.taskId);
-        if (decoration == null) return false;
+        if (decoration == null) return;
 
         decoration.relayout(taskInfo, startT, finishT);
-        return true;
     }
 
     @Override
-    public boolean destroyWindowDecoration(RunningTaskInfo taskInfo) {
+    public void destroyWindowDecoration(RunningTaskInfo taskInfo) {
         final CaptionWindowDecoration decoration =
                 mWindowDecorByTaskId.removeReturnOld(taskInfo.taskId);
-        if (decoration == null) return false;
+        if (decoration == null) return;
 
         decoration.close();
-        return true;
     }
 
     private class CaptionTouchEventListener implements
@@ -217,6 +242,7 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
                 decoration.setButtonVisibility();
             }
         }
+
         private void injectBackKey() {
             sendBackEvent(KeyEvent.ACTION_DOWN);
             sendBackEvent(KeyEvent.ACTION_UP);
@@ -266,7 +292,7 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
          */
         private void handleEventForMove(MotionEvent e) {
             RunningTaskInfo taskInfo = mTaskOrganizer.getRunningTaskInfo(mTaskId);
-            int windowingMode =  mDesktopModeController
+            int windowingMode = mDesktopModeController
                     .getDisplayAreaWindowingMode(taskInfo.displayId);
             if (windowingMode == WINDOWING_MODE_FULLSCREEN) {
                 return;
@@ -302,7 +328,7 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
     }
 
     // InputEventReceiver to listen for touch input outside of caption bounds
-    private class EventReceiver extends InputEventReceiver {
+    class EventReceiver extends InputEventReceiver {
         EventReceiver(InputChannel channel, Looper looper) {
             super(channel, looper);
         }
@@ -318,8 +344,15 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
         }
     }
 
+    class EventReceiverFactory {
+        EventReceiver create(InputChannel channel, Looper looper) {
+            return new EventReceiver(channel, looper);
+        }
+    }
+
     /**
      * Handle MotionEvents relevant to focused task's caption that don't directly touch it
+     *
      * @param ev the {@link MotionEvent} received by {@link EventReceiver}
      */
     private void handleReceivedMotionEvent(MotionEvent ev) {
@@ -401,7 +434,6 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
         return focusedDecor;
     }
 
-
     private boolean shouldShowWindowDecor(RunningTaskInfo taskInfo) {
         if (taskInfo.getWindowingMode() == WINDOWING_MODE_FREEFORM) return true;
         return DesktopModeStatus.IS_SUPPORTED
@@ -410,7 +442,47 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
                 .getResources().getConfiguration().smallestScreenWidthDp >= 600;
     }
 
-    private class DragStartListenerImpl implements TaskPositioner.DragStartListener{
+    private void createWindowDecoration(
+            ActivityManager.RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        CaptionWindowDecoration oldDecoration = mWindowDecorByTaskId.get(taskInfo.taskId);
+        if (oldDecoration != null) {
+            // close the old decoration if it exists to avoid two window decorations being added
+            oldDecoration.close();
+        }
+        final CaptionWindowDecoration windowDecoration =
+                mCaptionWindowDecorFactory.create(
+                        mContext,
+                        mDisplayController,
+                        mTaskOrganizer,
+                        taskInfo,
+                        taskSurface,
+                        mMainHandler,
+                        mMainChoreographer,
+                        mSyncQueue);
+        mWindowDecorByTaskId.put(taskInfo.taskId, windowDecoration);
+
+        TaskPositioner taskPositioner =
+                new TaskPositioner(mTaskOrganizer, windowDecoration, mDragStartListener);
+        CaptionTouchEventListener touchEventListener =
+                new CaptionTouchEventListener(
+                        taskInfo, taskPositioner, windowDecoration.getDragDetector());
+        windowDecoration.setCaptionListeners(touchEventListener, touchEventListener);
+        windowDecoration.setDragResizeCallback(taskPositioner);
+        windowDecoration.relayout(taskInfo, startT, finishT);
+        if (mInputMonitor == null) {
+            InputManager inputManager = mInputManagerSupplier.get();
+            mInputMonitor =
+                    inputManager.monitorGestureInput("caption-touch", mContext.getDisplayId());
+            mEventReceiver =
+                    mEventReceiverFactory.create(
+                            mInputMonitor.getInputChannel(), Looper.myLooper());
+        }
+    }
+
+    private class DragStartListenerImpl implements TaskPositioner.DragStartListener {
         @Override
         public void onDragStart(int taskId) {
             mWindowDecorByTaskId.get(taskId).closeHandleMenu();
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
index 59576cd3ec15..037ca2031254 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecoration.java
@@ -42,7 +42,8 @@ import com.android.wm.shell.desktopmode.DesktopModeStatus;
 
 /**
  * Defines visuals and behaviors of a window decoration of a caption bar and shadows. It works with
- * {@link CaptionWindowDecorViewModel}. The caption bar contains a handle, back button, and close button.
+ * {@link CaptionWindowDecorViewModel}. The caption bar contains a handle, back button, and close
+ * button.
  *
  * The shadow's thickness is 20dp when the window is in focus and 5dp when the window isn't.
  */
@@ -181,12 +182,12 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
         if (oldDecorationSurface != mDecorationContainerSurface || mDragResizeListener == null) {
             closeDragResizeListener();
             mDragResizeListener = new DragResizeInputListener(
-                        mContext,
-                        mHandler,
-                        mChoreographer,
-                        mDisplay.getDisplayId(),
-                        mDecorationContainerSurface,
-                        mDragResizeCallback);
+                    mContext,
+                    mHandler,
+                    mChoreographer,
+                    mDisplay.getDisplayId(),
+                    mDecorationContainerSurface,
+                    mDragResizeCallback);
         }
 
         int touchSlop = ViewConfiguration.get(mResult.mRootView.getContext()).getScaledTouchSlop();
@@ -242,7 +243,6 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
 
     /**
      * Sets the visibility of buttons and color of caption based on desktop mode status
-     *
      */
     void setButtonVisibility() {
         mDesktopActive = DesktopModeStatus.isActive(mContext);
@@ -313,6 +313,7 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
 
     /**
      * Close an open handle menu if input is outside of menu coordinates
+     *
      * @param ev the tapped point to compare against
      */
     void closeHandleMenuIfNeeded(MotionEvent ev) {
@@ -329,6 +330,7 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
 
     /**
      * Offset the coordinates of a {@link MotionEvent} to be in the same coordinate space as caption
+     *
      * @param ev the {@link MotionEvent} to offset
      * @return the point of the input in local space
      */
@@ -343,7 +345,8 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
 
     /**
      * Determine if a passed MotionEvent is in a view in caption
-     * @param ev the {@link MotionEvent} to check
+     *
+     * @param ev       the {@link MotionEvent} to check
      * @param layoutId the id of the view
      * @return {@code true} if event is inside the specified view, {@code false} if not
      */
@@ -363,6 +366,7 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
      * Check a passed MotionEvent if a click has occurred on any button on this caption
      * Note this should only be called when a regular onClick is not possible
      * (i.e. the button was clicked through status bar layer)
+     *
      * @param ev the MotionEvent to compare
      */
     void checkClickEvent(MotionEvent ev) {
@@ -399,4 +403,27 @@ public class CaptionWindowDecoration extends WindowDecoration<WindowDecorLinearL
         closeHandleMenu();
         super.close();
     }
+
+    static class Factory {
+
+        CaptionWindowDecoration create(
+                Context context,
+                DisplayController displayController,
+                ShellTaskOrganizer taskOrganizer,
+                ActivityManager.RunningTaskInfo taskInfo,
+                SurfaceControl taskSurface,
+                Handler handler,
+                Choreographer choreographer,
+                SyncTransactionQueue syncQueue) {
+            return new CaptionWindowDecoration(
+                    context,
+                    displayController,
+                    taskOrganizer,
+                    taskInfo,
+                    taskSurface,
+                    handler,
+                    choreographer,
+                    syncQueue);
+        }
+    }
 }
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java
index 2ce4d04377a1..907977c661f8 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java
@@ -28,7 +28,6 @@ import com.android.wm.shell.freeform.FreeformTaskTransitionStarter;
  * servers.
  */
 public interface WindowDecorViewModel {
-
     /**
      * Sets the transition starter that starts freeform task transitions.
      *
@@ -37,16 +36,16 @@ public interface WindowDecorViewModel {
     void setFreeformTaskTransitionStarter(FreeformTaskTransitionStarter transitionStarter);
 
     /**
-     * Creates a window decoration for the given task.
-     * Can be {@code null} for Fullscreen tasks but not Freeform ones.
+     * Creates a window decoration for the given task. Can be {@code null} for Fullscreen tasks but
+     * not Freeform ones.
      *
-     * @param taskInfo the initial task info of the task
+     * @param taskInfo    the initial task info of the task
      * @param taskSurface the surface of the task
-     * @param startT the start transaction to be applied before the transition
-     * @param finishT the finish transaction to restore states after the transition
+     * @param startT      the start transaction to be applied before the transition
+     * @param finishT     the finish transaction to restore states after the transition
      * @return {@code true} if window decoration was created, {@code false} otherwise
      */
-    boolean createWindowDecoration(
+    boolean onTaskOpening(
             ActivityManager.RunningTaskInfo taskInfo,
             SurfaceControl taskSurface,
             SurfaceControl.Transaction startT,
@@ -54,7 +53,7 @@ public interface WindowDecorViewModel {
 
     /**
      * Notifies a task info update on the given task, with the window decoration created previously
-     * for this task by {@link #createWindowDecoration}.
+     * for this task by {@link #onTaskOpening}.
      *
      * @param taskInfo the new task info of the task
      */
@@ -62,13 +61,29 @@ public interface WindowDecorViewModel {
 
     /**
      * Notifies a transition is about to start about the given task to give the window decoration a
-     * chance to prepare for this transition.
+     * chance to prepare for this transition. Unlike {@link #onTaskInfoChanged}, this method creates
+     * a window decoration if one does not exist but is required.
+     *
+     * @param taskInfo    the initial task info of the task
+     * @param taskSurface the surface of the task
+     * @param startT      the start transaction to be applied before the transition
+     * @param finishT     the finish transaction to restore states after the transition
+     */
+    void onTaskChanging(
+            ActivityManager.RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT);
+
+    /**
+     * Notifies that the given task is about to close to give the window decoration a chance to
+     * prepare for this transition.
      *
-     * @param startT the start transaction to be applied before the transition
-     * @param finishT the finish transaction to restore states after the transition
-     * @return {@code true} if window decoration exists, {@code false} otherwise
+     * @param taskInfo the initial task info of the task
+     * @param startT   the start transaction to be applied before the transition
+     * @param finishT  the finish transaction to restore states after the transition
      */
-    boolean setupWindowDecorationForTransition(
+    void onTaskClosing(
             ActivityManager.RunningTaskInfo taskInfo,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT);
@@ -77,7 +92,6 @@ public interface WindowDecorViewModel {
      * Destroys the window decoration of the give task.
      *
      * @param taskInfo the info of the task
-     * @return {@code true} if window decoration was destroyed, {@code false} otherwise
      */
-    boolean destroyWindowDecoration(ActivityManager.RunningTaskInfo taskInfo);
-}
+    void destroyWindowDecoration(ActivityManager.RunningTaskInfo taskInfo);
+}
\ No newline at end of file
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserverTest.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserverTest.java
index 7068a84c3056..48415d47304c 100644
--- a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserverTest.java
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserverTest.java
@@ -103,7 +103,7 @@ public class FreeformTaskTransitionObserverTest {
         mTransitionObserver.onTransitionReady(transition, info, startT, finishT);
         mTransitionObserver.onTransitionStarting(transition);
 
-        verify(mWindowDecorViewModel).createWindowDecoration(
+        verify(mWindowDecorViewModel).onTaskOpening(
                 change.getTaskInfo(), change.getLeash(), startT, finishT);
     }
 
@@ -120,7 +120,7 @@ public class FreeformTaskTransitionObserverTest {
         mTransitionObserver.onTransitionReady(transition, info, startT, finishT);
         mTransitionObserver.onTransitionStarting(transition);
 
-        verify(mWindowDecorViewModel).setupWindowDecorationForTransition(
+        verify(mWindowDecorViewModel).onTaskClosing(
                 change.getTaskInfo(), startT, finishT);
     }
 
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModelTests.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModelTests.java
new file mode 100644
index 000000000000..8b134ed1dfe4
--- /dev/null
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModelTests.java
@@ -0,0 +1,217 @@
+/*
+ * Copyright (C) 2022 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.wm.shell.windowdecor;
+
+import static android.app.WindowConfiguration.ACTIVITY_TYPE_STANDARD;
+import static android.app.WindowConfiguration.ACTIVITY_TYPE_UNDEFINED;
+import static android.app.WindowConfiguration.WINDOWING_MODE_FREEFORM;
+import static android.app.WindowConfiguration.WINDOWING_MODE_UNDEFINED;
+
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyInt;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.ActivityManager;
+import android.hardware.input.InputManager;
+import android.os.Handler;
+import android.os.Looper;
+import android.view.Choreographer;
+import android.view.Display;
+import android.view.InputChannel;
+import android.view.InputMonitor;
+import android.view.SurfaceControl;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.rule.GrantPermissionRule;
+
+import com.android.wm.shell.ShellTaskOrganizer;
+import com.android.wm.shell.ShellTestCase;
+import com.android.wm.shell.TestRunningTaskInfoBuilder;
+import com.android.wm.shell.common.DisplayController;
+import com.android.wm.shell.common.SyncTransactionQueue;
+import com.android.wm.shell.desktopmode.DesktopModeController;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Supplier;
+
+/** Tests of {@link CaptionWindowDecorViewModel} */
+@SmallTest
+public class CaptionWindowDecorViewModelTests extends ShellTestCase {
+    @Mock private CaptionWindowDecoration mCaptionWindowDecoration;
+
+    @Mock private CaptionWindowDecoration.Factory mCaptionWindowDecorFactory;
+
+    @Mock private Handler mMainHandler;
+
+    @Mock private Choreographer mMainChoreographer;
+
+    @Mock private ShellTaskOrganizer mTaskOrganizer;
+
+    @Mock private DisplayController mDisplayController;
+
+    @Mock private SyncTransactionQueue mSyncQueue;
+
+    @Mock private DesktopModeController mDesktopModeController;
+
+    @Mock private InputMonitor mInputMonitor;
+
+    @Mock private InputChannel mInputChannel;
+
+    @Mock private CaptionWindowDecorViewModel.EventReceiverFactory mEventReceiverFactory;
+
+    @Mock private CaptionWindowDecorViewModel.EventReceiver mEventReceiver;
+
+    @Mock private InputManager mInputManager;
+
+    private final List<InputManager> mMockInputManagers = new ArrayList<>();
+
+    private CaptionWindowDecorViewModel mCaptionWindowDecorViewModel;
+
+    @Before
+    public void setUp() {
+        mMockInputManagers.add(mInputManager);
+
+        mCaptionWindowDecorViewModel =
+            new CaptionWindowDecorViewModel(
+                mContext,
+                mMainHandler,
+                mMainChoreographer,
+                mTaskOrganizer,
+                mDisplayController,
+                mSyncQueue,
+                mDesktopModeController,
+                mCaptionWindowDecorFactory,
+                new MockObjectSupplier<>(mMockInputManagers, () -> mock(InputManager.class)));
+        mCaptionWindowDecorViewModel.setEventReceiverFactory(mEventReceiverFactory);
+
+        doReturn(mCaptionWindowDecoration)
+            .when(mCaptionWindowDecorFactory)
+            .create(any(), any(), any(), any(), any(), any(), any(), any());
+
+        when(mInputManager.monitorGestureInput(any(), anyInt())).thenReturn(mInputMonitor);
+        when(mEventReceiverFactory.create(any(), any())).thenReturn(mEventReceiver);
+        when(mInputMonitor.getInputChannel()).thenReturn(mInputChannel);
+    }
+
+    @Test
+    public void testDeleteCaptionOnChangeTransitionWhenNecessary() throws Exception {
+        Looper.prepare();
+        final int taskId = 1;
+        final ActivityManager.RunningTaskInfo taskInfo =
+                createTaskInfo(taskId, WINDOWING_MODE_FREEFORM);
+        SurfaceControl surfaceControl = mock(SurfaceControl.class);
+        final SurfaceControl.Transaction startT = mock(SurfaceControl.Transaction.class);
+        final SurfaceControl.Transaction finishT = mock(SurfaceControl.Transaction.class);
+        GrantPermissionRule.grant(android.Manifest.permission.MONITOR_INPUT);
+
+        mCaptionWindowDecorViewModel.onTaskOpening(taskInfo, surfaceControl, startT, finishT);
+        verify(mCaptionWindowDecorFactory)
+                .create(
+                    mContext,
+                    mDisplayController,
+                    mTaskOrganizer,
+                    taskInfo,
+                    surfaceControl,
+                    mMainHandler,
+                    mMainChoreographer,
+                    mSyncQueue);
+
+        taskInfo.configuration.windowConfiguration.setWindowingMode(WINDOWING_MODE_UNDEFINED);
+        taskInfo.configuration.windowConfiguration.setActivityType(ACTIVITY_TYPE_UNDEFINED);
+        mCaptionWindowDecorViewModel.onTaskChanging(taskInfo, surfaceControl, startT, finishT);
+        verify(mCaptionWindowDecoration).close();
+    }
+
+    @Test
+    public void testCreateCaptionOnChangeTransitionWhenNecessary() throws Exception {
+        final int taskId = 1;
+        final ActivityManager.RunningTaskInfo taskInfo =
+                createTaskInfo(taskId, WINDOWING_MODE_UNDEFINED);
+        SurfaceControl surfaceControl = mock(SurfaceControl.class);
+        final SurfaceControl.Transaction startT = mock(SurfaceControl.Transaction.class);
+        final SurfaceControl.Transaction finishT = mock(SurfaceControl.Transaction.class);
+        taskInfo.configuration.windowConfiguration.setActivityType(ACTIVITY_TYPE_UNDEFINED);
+
+        mCaptionWindowDecorViewModel.onTaskChanging(taskInfo, surfaceControl, startT, finishT);
+
+        verify(mCaptionWindowDecorFactory, never())
+                .create(
+                    mContext,
+                    mDisplayController,
+                    mTaskOrganizer,
+                    taskInfo,
+                    surfaceControl,
+                    mMainHandler,
+                    mMainChoreographer,
+                    mSyncQueue);
+
+        taskInfo.configuration.windowConfiguration.setWindowingMode(WINDOWING_MODE_FREEFORM);
+        taskInfo.configuration.windowConfiguration.setActivityType(ACTIVITY_TYPE_STANDARD);
+
+        mCaptionWindowDecorViewModel.onTaskChanging(taskInfo, surfaceControl, startT, finishT);
+
+        verify(mCaptionWindowDecorFactory)
+                .create(
+                    mContext,
+                    mDisplayController,
+                    mTaskOrganizer,
+                    taskInfo,
+                    surfaceControl,
+                    mMainHandler,
+                    mMainChoreographer,
+                    mSyncQueue);
+    }
+
+    private static ActivityManager.RunningTaskInfo createTaskInfo(int taskId, int windowingMode) {
+        ActivityManager.RunningTaskInfo taskInfo =
+                 new TestRunningTaskInfoBuilder()
+                .setDisplayId(Display.DEFAULT_DISPLAY)
+                .setVisible(true)
+                .build();
+        taskInfo.taskId = taskId;
+        taskInfo.configuration.windowConfiguration.setWindowingMode(windowingMode);
+        return taskInfo;
+    }
+
+    private static class MockObjectSupplier<T> implements Supplier<T> {
+        private final List<T> mObjects;
+        private final Supplier<T> mDefaultSupplier;
+        private int mNumOfCalls = 0;
+
+        private MockObjectSupplier(List<T> objects, Supplier<T> defaultSupplier) {
+            mObjects = objects;
+            mDefaultSupplier = defaultSupplier;
+        }
+
+        @Override
+        public T get() {
+            final T mock =
+                    mNumOfCalls < mObjects.size() ? mObjects.get(mNumOfCalls)
+                        : mDefaultSupplier.get();
+            ++mNumOfCalls;
+            return mock;
+        }
+    }
+}