Web Animations: Introduce ActiveAnimations and AnimationStack

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 25 matching lines @@
 #include "wtf/RefPtr.h"
 
 namespace WebCore {
 
 class Element;
 
 class Animation FINAL : public TimedItem {
 
 public:
     static PassRefPtr<Animation> create(PassRefPtr<Element>, PassRefPtr<AnimationEffect>, const Timing&);
-    virtual ~Animation();
 
     const AnimationEffect::CompositableValueMap* compositableValues() const
     {
         ASSERT(m_compositableValues);
         return m_compositableValues.get();
     }
 
 protected:
     virtual void applyEffects(bool previouslyActiveOrInEffect);
     virtual void clearEffects();
     virtual void updateChildrenAndEffects(bool) const OVERRIDE FINAL;
+    virtual void willDetach() OVERRIDE FINAL;
 
 private:
     Animation(PassRefPtr<Element>, PassRefPtr<AnimationEffect>, const Timing&);
 
     RefPtr<Element> m_target;
     RefPtr<AnimationEffect> m_effect;
-    bool m_isInTargetActiveAnimationsList;
+
+    bool m_activeInAnimationStack;
     OwnPtr<AnimationEffect::CompositableValueMap> m_compositableValues;
 };
 
 } // namespace WebCore
 
 #endif