Rework dispatchEvent so it is consistent for isTrusted support.

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 625 matching lines @@
 }
 
 void Animation::stop()
 {
     PlayStateUpdateScope updateScope(*this, TimingUpdateOnDemand);
 
     m_finished = true;
     m_pendingFinishedEvent = nullptr;
 }
 
-bool Animation::dispatchEvent(PassRefPtrWillBeRawPtr<Event> event)
+bool Animation::dispatchEventInternal(PassRefPtrWillBeRawPtr<Event> event)
 {
     if (m_pendingFinishedEvent == event)
         m_pendingFinishedEvent = nullptr;
-    return EventTargetWithInlineData::dispatchEvent(event);
+    return EventTargetWithInlineData::dispatchEventInternal(event);
 }
 
 double Animation::playbackRate() const
 {
     return m_playbackRate;
 }
 
 void Animation::setPlaybackRate(double playbackRate)
 {
     if (playbackRate == m_playbackRate)
@@ skipping 427 matching lines @@
     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