ResolverListAdapter: Switch `Handler`->`Executor`

With the new `mDestroyed` bookkeeping in ag/24854314, we no longer
need the richer (but less-testable/etc) API of a `Handler`.

In the first snapshot, this retains the ad-hoc flow control mechanisms
that direct the `testPostListReadyAtEndOfRebuild_` tests to show the
direct before-and-after equivalence against the `Handler` model. All
the existing tests still pass on the new code.

The second snapshot removes those ad-hoc mechanisms because the tests
now have complete control of the execution via `TestExecutor`.

Bug: (general code cleanup)
Test: `IntentResolverUnitTests` / `CtsSharesheetDeviceTest`
Change-Id: I3063d45aedec47a81bf9bc7f76c26873de1383af

1 files changed, 11 insertions, 12 deletions

diff --git a/java/src/com/android/intentresolver/ResolverListAdapter.java b/java/src/com/android/intentresolver/ResolverListAdapter.java
index 4ad8d926..0d199fa3 100644
--- a/java/src/com/android/intentresolver/ResolverListAdapter.java
+++ b/java/src/com/android/intentresolver/ResolverListAdapter.java
@@ -28,7 +28,6 @@ import android.graphics.ColorMatrix;
 import android.graphics.ColorMatrixColorFilter;
 import android.graphics.drawable.Drawable;
 import android.os.AsyncTask;
-import android.os.Handler;
 import android.os.RemoteException;
 import android.os.Trace;
 import android.os.UserHandle;
@@ -82,7 +81,7 @@ public class ResolverListAdapter extends BaseAdapter {
     private final Set<DisplayResolveInfo> mRequestedIcons = new HashSet<>();
     private final Set<DisplayResolveInfo> mRequestedLabels = new HashSet<>();
     private final Executor mBgExecutor;
-    private final Handler mMainHandler;
+    private final Executor mCallbackExecutor;
     private final AtomicBoolean mDestroyed = new AtomicBoolean();
 
     private ResolveInfo mLastChosen;
@@ -124,7 +123,7 @@ public class ResolverListAdapter extends BaseAdapter {
                 initialIntentsUserSpace,
                 targetDataLoader,
                 AsyncTask.SERIAL_EXECUTOR,
-                context.getMainThreadHandler());
+                runnable -> context.getMainThreadHandler().post(runnable));
     }
 
     @VisibleForTesting
@@ -141,7 +140,7 @@ public class ResolverListAdapter extends BaseAdapter {
             UserHandle initialIntentsUserSpace,
             TargetDataLoader targetDataLoader,
             Executor bgExecutor,
-            Handler mainHandler) {
+            Executor callbackExecutor) {
         mContext = context;
         mIntents = payloadIntents;
         mInitialIntents = initialIntents;
@@ -157,7 +156,7 @@ public class ResolverListAdapter extends BaseAdapter {
         mResolverListCommunicator = resolverListCommunicator;
         mInitialIntentsUserSpace = initialIntentsUserSpace;
         mBgExecutor = bgExecutor;
-        mMainHandler = mainHandler;
+        mCallbackExecutor = callbackExecutor;
     }
 
     public final DisplayResolveInfo getFirstDisplayResolveInfo() {
@@ -236,12 +235,12 @@ public class ResolverListAdapter extends BaseAdapter {
 
     /**
      * Rebuild the list of resolvers. When rebuilding is complete, queue the {@code onPostListReady}
-     * callback on the main handler with {@code rebuildCompleted} true.
+     * callback on the callback executor with {@code rebuildCompleted} true.
      *
      * In some cases some parts will need some asynchronous work to complete. Then this will first
-     * immediately queue {@code onPostListReady} (on the main handler) with {@code rebuildCompleted}
-     * false; only when the asynchronous work completes will this then go on to queue another
-     * {@code onPostListReady} callback with {@code rebuildCompleted} true.
+     * immediately queue {@code onPostListReady} (on the callback executor) with
+     * {@code rebuildCompleted} false; only when the asynchronous work completes will this then go
+     * on to queue another {@code onPostListReady} callback with {@code rebuildCompleted} true.
      *
      * The {@code doPostProcessing} parameter is used to specify whether to update the UI and
      * load additional targets (e.g. direct share) after the list has been rebuilt. We may choose
@@ -456,7 +455,7 @@ public class ResolverListAdapter extends BaseAdapter {
                 throw t;
             } finally {
                 final List<ResolvedComponentInfo> result = sortedComponents;
-                mMainHandler.post(() -> onComponentsSorted(result, doPostProcessing));
+                mCallbackExecutor.execute(() -> onComponentsSorted(result, doPostProcessing));
             }
         });
         return false;
@@ -541,7 +540,7 @@ public class ResolverListAdapter extends BaseAdapter {
     /**
      * Some necessary methods for creating the list are initiated in onCreate and will also
      * determine the layout known. We therefore can't update the UI inline and post to the
-     * handler thread to update after the current task is finished.
+     * callback executor to update after the current task is finished.
      * @param doPostProcessing Whether to update the UI and load additional direct share targets
      *                         after the list has been rebuilt
      * @param rebuildCompleted Whether the list has been completely rebuilt
@@ -557,7 +556,7 @@ public class ResolverListAdapter extends BaseAdapter {
                         doPostProcessing, rebuildCompleted);
             }
         };
-        mMainHandler.post(listReadyRunnable);
+        mCallbackExecutor.execute(listReadyRunnable);
     }
 
     private void addResolveInfoWithAlternates(ResolvedComponentInfo rci) {