Blink Animation: Extend Animation's GC lifetime if it has a finish promise.

third_party/WebKit/Source/core/animation/Animation.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 633 matching lines @@
 
 const AtomicString& Animation::interfaceName() const {
   return EventTargetNames::AnimationPlayer;
 }
 
 ExecutionContext* Animation::getExecutionContext() const {
   return ActiveDOMObject::getExecutionContext();
 }
 
 bool Animation::hasPendingActivity() const {
-  return m_pendingFinishedEvent ||
+  bool hasPendingPromise =
+      !m_finished && m_finishedPromise &&
+      m_finishedPromise->getState() == ScriptPromisePropertyBase::Pending;
+
+  return m_pendingFinishedEvent || hasPendingPromise ||
          (!m_finished && hasEventListeners(EventTypeNames::finish));
 }
 
 void Animation::contextDestroyed() {
   PlayStateUpdateScope updateScope(*this, TimingUpdateOnDemand);
 
   m_finished = true;
   m_pendingFinishedEvent = nullptr;
 }
 
@@ skipping 455 matching lines @@
   visitor->trace(m_timeline);
   visitor->trace(m_pendingFinishedEvent);
   visitor->trace(m_pendingCancelledEvent);
   visitor->trace(m_finishedPromise);
   visitor->trace(m_readyPromise);
   EventTargetWithInlineData::trace(visitor);
   ActiveDOMObject::trace(visitor);
 }
 
 }  // namespace blink