Web Animations CSS: Unfreeze AnimationClock if sampling timelines does not trigger style recalc

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 38 matching lines @@
     const AnimationEffect::CompositableValueMap* compositableValues() const
     {
         ASSERT(m_compositableValues);
         return m_compositableValues.get();
     }
 
     const AnimationEffect* effect() const { return m_effect.get(); }
     Priority priority() const { return m_priority; }
 
 protected:
-    virtual void applyEffects(bool previouslyInEffect);
+    // Returns whether style recalc was triggered.
+    virtual bool applyEffects(bool previouslyInEffect);
     virtual void clearEffects();
-    virtual void updateChildrenAndEffects() const OVERRIDE FINAL;
+    virtual bool updateChildrenAndEffects() const OVERRIDE FINAL;
     virtual void willDetach() OVERRIDE FINAL;
     virtual double calculateTimeToEffectChange(double inheritedTime, double activeTime, Phase) const OVERRIDE FINAL;
 
 private:
     Animation(PassRefPtr<Element>, PassRefPtr<AnimationEffect>, const Timing&, Priority, PassOwnPtr<EventDelegate>);
 
     RefPtr<Element> m_target;
     RefPtr<AnimationEffect> m_effect;
 
     bool m_activeInAnimationStack;
     OwnPtr<AnimationEffect::CompositableValueMap> m_compositableValues;
 
     Priority m_priority;
 };
 
 } // namespace WebCore
 
 #endif