Make sure app transition are started simultaneously

Test: go/wm-smoke
Test: Lock device in split screen, make sure everything is
absolutely synchronized when unlocking

Bug: 64674361
Change-Id: I25352d7a6b8beb9729310dd525710dca20a78166

3 files changed, 69 insertions, 17 deletions

diff --git a/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java b/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java
index 3a41eb0e2afc..dc62cc89c14d 100644
--- a/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java
+++ b/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java
@@ -67,6 +67,9 @@ class SurfaceAnimationRunner {
     @VisibleForTesting
     final ArrayMap<SurfaceControl, RunningAnimation> mRunningAnimations = new ArrayMap<>();
 
+    @GuardedBy("mLock")
+    private boolean mAnimationStartDeferred;
+
     SurfaceAnimationRunner() {
         this(null /* callbackProvider */, null /* animatorFactory */, new Transaction());
     }
@@ -86,13 +89,41 @@ class SurfaceAnimationRunner {
                 : SfValueAnimator::new;
     }
 
+    /**
+     * Defers starting of animations until {@link #continueStartingAnimations} is called. This
+     * method is NOT nestable.
+     *
+     * @see #continueStartingAnimations
+     */
+    void deferStartingAnimations() {
+        synchronized (mLock) {
+            mAnimationStartDeferred = true;
+        }
+    }
+
+    /**
+     * Continues starting of animations.
+     *
+     * @see #deferStartingAnimations
+     */
+    void continueStartingAnimations() {
+        synchronized (mLock) {
+            mAnimationStartDeferred = false;
+            if (!mPendingAnimations.isEmpty()) {
+                mChoreographer.postFrameCallback(this::startAnimations);
+            }
+        }
+    }
+
     void startAnimation(AnimationSpec a, SurfaceControl animationLeash, Transaction t,
             Runnable finishCallback) {
         synchronized (mLock) {
             final RunningAnimation runningAnim = new RunningAnimation(a, animationLeash,
                     finishCallback);
             mPendingAnimations.put(animationLeash, runningAnim);
-            mChoreographer.postFrameCallback(this::stepAnimation);
+            if (!mAnimationStartDeferred) {
+                mChoreographer.postFrameCallback(this::startAnimations);
+            }
 
             // Some animations (e.g. move animations) require the initial transform to be applied
             // immediately.
@@ -185,7 +216,7 @@ class SurfaceAnimationRunner {
         a.mAnimSpec.apply(t, a.mLeash, currentPlayTime);
     }
 
-    private void stepAnimation(long frameTimeNanos) {
+    private void startAnimations(long frameTimeNanos) {
         synchronized (mLock) {
             startPendingAnimationsLocked();
         }
diff --git a/services/core/java/com/android/server/wm/WindowSurfacePlacer.java b/services/core/java/com/android/server/wm/WindowSurfacePlacer.java
index bdab9c765d36..08f49f689323 100644
--- a/services/core/java/com/android/server/wm/WindowSurfacePlacer.java
+++ b/services/core/java/com/android/server/wm/WindowSurfacePlacer.java
@@ -349,21 +349,28 @@ class WindowSurfacePlacer {
             animLp = null;
         }
 
-        processApplicationsAnimatingInPlace(transit);
-
-        mTmpLayerAndToken.token = null;
-        handleClosingApps(transit, animLp, voiceInteraction, mTmpLayerAndToken);
-        final AppWindowToken topClosingApp = mTmpLayerAndToken.token;
-        final AppWindowToken topOpeningApp = handleOpeningApps(transit, animLp, voiceInteraction);
-
-        mService.mAppTransition.setLastAppTransition(transit, topOpeningApp, topClosingApp);
-
-        final int flags = mService.mAppTransition.getTransitFlags();
-        int layoutRedo = mService.mAppTransition.goodToGo(transit, topOpeningApp,
-                topClosingApp, mService.mOpeningApps, mService.mClosingApps);
-        handleNonAppWindowsInTransition(transit, flags);
-        mService.mAppTransition.postAnimationCallback();
-        mService.mAppTransition.clear();
+        final int layoutRedo;
+        mService.mSurfaceAnimationRunner.deferStartingAnimations();
+        try {
+            processApplicationsAnimatingInPlace(transit);
+
+            mTmpLayerAndToken.token = null;
+            handleClosingApps(transit, animLp, voiceInteraction, mTmpLayerAndToken);
+            final AppWindowToken topClosingApp = mTmpLayerAndToken.token;
+            final AppWindowToken topOpeningApp = handleOpeningApps(transit, animLp,
+                    voiceInteraction);
+
+            mService.mAppTransition.setLastAppTransition(transit, topOpeningApp, topClosingApp);
+
+            final int flags = mService.mAppTransition.getTransitFlags();
+            layoutRedo = mService.mAppTransition.goodToGo(transit, topOpeningApp,
+                    topClosingApp, mService.mOpeningApps, mService.mClosingApps);
+            handleNonAppWindowsInTransition(transit, flags);
+            mService.mAppTransition.postAnimationCallback();
+            mService.mAppTransition.clear();
+        } finally {
+            mService.mSurfaceAnimationRunner.continueStartingAnimations();
+        }
 
         mService.mTaskSnapshotController.onTransitionStarting();
 
diff --git a/services/tests/servicestests/src/com/android/server/wm/SurfaceAnimationRunnerTest.java b/services/tests/servicestests/src/com/android/server/wm/SurfaceAnimationRunnerTest.java
index 17fe6427f756..4831fcd67314 100644
--- a/services/tests/servicestests/src/com/android/server/wm/SurfaceAnimationRunnerTest.java
+++ b/services/tests/servicestests/src/com/android/server/wm/SurfaceAnimationRunnerTest.java
@@ -162,6 +162,20 @@ public class SurfaceAnimationRunnerTest extends WindowTestsBase {
         verify(mMockAnimationSpec, atLeastOnce()).apply(any(), any(), eq(0L));
     }
 
+    @Test
+    public void testDeferStartingAnimations() throws Exception {
+        mSurfaceAnimationRunner.deferStartingAnimations();
+        mSurfaceAnimationRunner.startAnimation(createTranslateAnimation(), mMockSurface,
+                mMockTransaction, this::finishedCallback);
+        waitUntilNextFrame();
+        assertTrue(mSurfaceAnimationRunner.mRunningAnimations.isEmpty());
+        mSurfaceAnimationRunner.continueStartingAnimations();
+        waitUntilNextFrame();
+        assertFalse(mSurfaceAnimationRunner.mRunningAnimations.isEmpty());
+        mFinishCallbackLatch.await(1, SECONDS);
+        assertFinishCallbackCalled();
+    }
+
     private void waitUntilNextFrame() throws Exception {
         final CountDownLatch latch = new CountDownLatch(1);
         mSurfaceAnimationRunner.mChoreographer.postCallback(Choreographer.CALLBACK_COMMIT,