Make sure launcher side can animate divider

Fix divider target should pass to remote animation runner and add
mIsDividerRemoteAnimating flag to eusure launcher side controlling
the divider surface and shell side do not controll until remote
animation finished.

Bug: 202914644
Test: manual
Test: pass existing tests
Change-Id: I6411a609268274355a38c72fcb5d628b76b2340c

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/SplitScreenController.java

@@ -374,7 +374,7 @@ public class SplitScreenController implements DragAndDropPolicy.Starter,
     }
 
     RemoteAnimationTarget[] onGoingToRecentsLegacy(boolean cancel, RemoteAnimationTarget[] apps) {
-        if (!isSplitScreenVisible()) return null;
+        if (apps.length < 2) return null;
         final SurfaceControl.Builder builder = new SurfaceControl.Builder(new SurfaceSession())
                 .setContainerLayer()
                 .setName("RecentsAnimationSplitTasks")

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java

@@ -369,6 +369,8 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
     void startTasksWithLegacyTransition(int mainTaskId, @Nullable Bundle mainOptions,
             int sideTaskId, @Nullable Bundle sideOptions, @SplitPosition int sidePosition,
             float splitRatio, RemoteAnimationAdapter adapter) {
+        // Init divider first to make divider leash for remote animation target.
+        mSplitLayout.init();
         final WindowContainerTransaction wct = new WindowContainerTransaction();
         // Need to add another wrapper here in shell so that we can inject the divider bar
         // and also manage the process elevation via setRunningRemote
@@ -385,6 +387,15 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
                     augmentedNonApps[i] = nonApps[i];
                 }
                 augmentedNonApps[augmentedNonApps.length - 1] = getDividerBarLegacyTarget();
+
+                IRemoteAnimationFinishedCallback wrapCallback =
+                        new IRemoteAnimationFinishedCallback.Stub() {
+                            @Override
+                            public void onAnimationFinished() throws RemoteException {
+                                mSyncQueue.runInSync(t -> setDividerVisibility(true, t));
+                                finishedCallback.onAnimationFinished();
+                            }
+                        };
                 try {
                     try {
                         ActivityTaskManager.getService().setRunningRemoteTransitionDelegate(
@@ -393,8 +404,8 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
                         Slog.e(TAG, "Unable to boost animation thread. This should only happen"
                                 + " during unit tests");
                     }
-                    adapter.getRunner().onAnimationStart(transit, apps, wallpapers, nonApps,
-                            finishedCallback);
+                    adapter.getRunner().onAnimationStart(transit, apps, wallpapers,
+                            augmentedNonApps, wrapCallback);
                 } catch (RemoteException e) {
                     Slog.e(TAG, "Error starting remote animation", e);
                 }
@@ -402,6 +413,7 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
 
             @Override
             public void onAnimationCancelled() {
+                mSyncQueue.runInSync(t -> setDividerVisibility(true, t));
                 try {
                     adapter.getRunner().onAnimationCancelled();
                 } catch (RemoteException e) {
@@ -868,9 +880,7 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
 
     private void applyDividerVisibility(SurfaceControl.Transaction t) {
         final SurfaceControl dividerLeash = mSplitLayout.getDividerLeash();
-        if (dividerLeash == null) {
-            return;
-        }
+        if (dividerLeash == null) return;
 
         if (mDividerVisible) {
             t.show(dividerLeash);
@@ -895,11 +905,15 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
             }
         } else if (isSideStage) {
             final WindowContainerTransaction wct = new WindowContainerTransaction();
+            mSplitLayout.init();
             // Make sure the main stage is active.
             mMainStage.activate(getMainStageBounds(), wct, true /* reparent */);
             mSideStage.moveToTop(getSideStageBounds(), wct);
             mSyncQueue.queue(wct);
-            mSyncQueue.runInSync(t -> updateSurfaceBounds(mSplitLayout, t));
+            mSyncQueue.runInSync(t -> {
+                updateSurfaceBounds(mSplitLayout, t);
+                setDividerVisibility(true, t);
+            });
         }
         if (mMainStageListener.mHasChildren && mSideStageListener.mHasChildren) {
             mShouldUpdateRecents = true;