Revert of Web Animations: Remove AnimationPlayer discarding logic

Source/core/animation/AnimationPlayer.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 881 matching lines @@
     default:
         ASSERT_NOT_REACHED();
         break;
     }
     m_player->endUpdatingState();
 
     if (oldPlayState != newPlayState && newPlayState == Running)
         InspectorInstrumentation::didCreateAnimationPlayer(m_player->timeline()->document(), *m_player);
 }
 
+
+#if !ENABLE(OILPAN)
+bool AnimationPlayer::canFree() const
+{
+    ASSERT(m_content);
+    return hasOneRef() && m_content->isAnimation() && m_content->hasOneRef();
+}
+#endif
+
 bool AnimationPlayer::addEventListener(const AtomicString& eventType, PassRefPtr<EventListener> listener, bool useCapture)
 {
     if (eventType == EventTypeNames::finish)
         UseCounter::count(executionContext(), UseCounter::AnimationPlayerFinishEvent);
     return EventTargetWithInlineData::addEventListener(eventType, listener, useCapture);
 }
 
 void AnimationPlayer::pauseForTesting(double pauseTime)
 {
     RELEASE_ASSERT(!paused());
     setCurrentTimeInternal(pauseTime, TimingUpdateOnDemand);
     if (hasActiveAnimationsOnCompositor())
         toAnimation(m_content.get())->pauseAnimationForTestingOnCompositor(currentTimeInternal());
     m_isPausedForTesting = true;
     pause();
 }
 
 DEFINE_TRACE(AnimationPlayer)
 {
     visitor->trace(m_content);
     visitor->trace(m_timeline);
     visitor->trace(m_pendingFinishedEvent);
     visitor->trace(m_finishedPromise);
     visitor->trace(m_readyPromise);
     EventTargetWithInlineData::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace