Rework dispatchEvent so it is consistent for isTrusted support.

Source/core/animation/Animation.h

 /*
  * 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 96 matching lines @@
     bool playing() const { return !(playStateInternal() == Idle || limited() || m_paused || m_isPausedForTesting); }
     bool limited() const { return limited(currentTimeInternal()); }
     bool finishedInternal() const { return m_finished; }
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(finish);
 
     const AtomicString& interfaceName() const override;
     ExecutionContext* executionContext() const override;
     bool hasPendingActivity() const override;
     void stop() override;
-    bool dispatchEvent(PassRefPtrWillBeRawPtr<Event>) override;
 
     double playbackRate() const;
     void setPlaybackRate(double);
     const AnimationTimeline* timeline() const { return m_timeline; }
     AnimationTimeline* timeline() { return m_timeline; }
 
 #if !ENABLE(OILPAN)
     void detachFromTimeline();
 #endif
 
@@ skipping 46 matching lines @@
 
     static bool hasLowerPriority(const Animation* animation1, const Animation* animation2)
     {
         return animation1->sequenceNumber() < animation2->sequenceNumber();
     }
 
     bool addEventListener(const AtomicString& eventType, PassRefPtr<EventListener>, bool useCapture = false) override;
 
     DECLARE_VIRTUAL_TRACE();
 
+protected:
+    bool dispatchEventInternal(PassRefPtrWillBeRawPtr<Event>) override;
+
 private:
     Animation(ExecutionContext*, AnimationTimeline&, AnimationEffect*);
 
     void clearOutdated();
 
     double effectEnd() const;
     bool limited(double currentTime) const;
 
     AnimationPlayState calculatePlayState();
     double calculateCurrentTime() const;
@@ skipping 101 matching lines @@
 
     OwnPtr<WebCompositorAnimationPlayer> m_compositorPlayer;
 
     bool m_currentTimePending;
     bool m_stateIsBeingUpdated;
 };
 
 } // namespace blink
 
 #endif // Animation_h