From 785334aeafcbe0932b8608771b24fa7aecda1a3b Mon Sep 17 00:00:00 2001
From: George Mount <mount@google.com>
Date: Thu, 19 Sep 2019 11:21:14 -0700
Subject: [PATCH] Clear reference to EnterTransitionCoordinator when done

Fixes: 141162306

When transitions have completed, the EnterTransitionCoordinator
is no longer needed, so should be cleared so that its references
can be released.

Test: ran code producing the leak
Change-Id: Ia049d88a45dc27b77fcf4ab58a444457a6b87f88
---
 .../android/app/ActivityTransitionState.java     | 12 ++++++++++--
 .../android/app/EnterTransitionCoordinator.java  | 16 ++++++++++++++--
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/core/java/android/app/ActivityTransitionState.java b/core/java/android/app/ActivityTransitionState.java
index 3a95839d2d122..0f9a6e63a1d29 100644
--- a/core/java/android/app/ActivityTransitionState.java
+++ b/core/java/android/app/ActivityTransitionState.java
@@ -197,13 +197,21 @@ class ActivityTransitionState {
         mHasExited = false;
         ArrayList<String> sharedElementNames = mEnterActivityOptions.getSharedElementNames();
         ResultReceiver resultReceiver = mEnterActivityOptions.getResultReceiver();
-        if (mEnterActivityOptions.isReturning()) {
+        final boolean isReturning = mEnterActivityOptions.isReturning();
+        if (isReturning) {
             restoreExitedViews();
             activity.getWindow().getDecorView().setVisibility(View.VISIBLE);
         }
         mEnterTransitionCoordinator = new EnterTransitionCoordinator(activity,
                 resultReceiver, sharedElementNames, mEnterActivityOptions.isReturning(),
-                mEnterActivityOptions.isCrossTask());
+                mEnterActivityOptions.isCrossTask(),
+                () -> {
+                    if (isReturning) {
+                        // once it is done transitioning, we don't need the coordinator --
+                        // if we kept it around, it could leak Views
+                        mEnterTransitionCoordinator = null;
+                    }
+                });
         if (mEnterActivityOptions.isCrossTask()) {
             mExitingFrom = new ArrayList<>(mEnterActivityOptions.getSharedElementNames());
             mExitingTo = new ArrayList<>(mEnterActivityOptions.getSharedElementNames());
diff --git a/core/java/android/app/EnterTransitionCoordinator.java b/core/java/android/app/EnterTransitionCoordinator.java
index bce243cc61086..905f47540fd99 100644
--- a/core/java/android/app/EnterTransitionCoordinator.java
+++ b/core/java/android/app/EnterTransitionCoordinator.java
@@ -18,6 +18,7 @@ package android.app;
 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.ObjectAnimator;
+import android.annotation.NonNull;
 import android.app.SharedElementCallback.OnSharedElementsReadyListener;
 import android.graphics.Color;
 import android.graphics.drawable.ColorDrawable;
@@ -66,13 +67,16 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
     private final boolean mIsCrossTask;
     private Drawable mReplacedBackground;
     private ArrayList<String> mPendingExitNames;
+    private Runnable mOnTransitionComplete;
 
-    public EnterTransitionCoordinator(Activity activity, ResultReceiver resultReceiver,
-            ArrayList<String> sharedElementNames, boolean isReturning, boolean isCrossTask) {
+    EnterTransitionCoordinator(Activity activity, ResultReceiver resultReceiver,
+            ArrayList<String> sharedElementNames, boolean isReturning, boolean isCrossTask,
+            @NonNull Runnable onTransitionComplete) {
         super(activity.getWindow(), sharedElementNames,
                 getListener(activity, isReturning && !isCrossTask), isReturning);
         mActivity = activity;
         mIsCrossTask = isCrossTask;
+        mOnTransitionComplete = onTransitionComplete;
         setResultReceiver(resultReceiver);
         prepareEnter();
         Bundle resultReceiverBundle = new Bundle();
@@ -578,6 +582,10 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
                 window.setBackgroundDrawable(null);
             }
         }
+        if (mOnTransitionComplete != null) {
+            mOnTransitionComplete.run();
+            mOnTransitionComplete = null;
+        }
     }
 
     private void sharedElementTransitionStarted() {
@@ -672,6 +680,10 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
             mBackgroundAnimator.cancel();
             mBackgroundAnimator = null;
         }
+        if (mOnTransitionComplete != null) {
+            mOnTransitionComplete.run();
+            mOnTransitionComplete = null;
+        }
         super.clearState();
     }