Update CSSAnimationUpdate and CSSAnimations to handle multiple animations with a given name

Source/core/animation/InertAnimation.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 24 matching lines @@
 #include "core/animation/TimedItem.h"
 #include "wtf/RefPtr.h"
 
 namespace WebCore {
 
 class InertAnimation FINAL : public TimedItem {
 
 public:
     static PassRefPtr<InertAnimation> create(PassRefPtr<AnimationEffect>, const Timing&);
     PassOwnPtr<AnimationEffect::CompositableValueMap> sample();
-    AnimationEffect* effect() { return m_effect.get(); }
+    AnimationEffect* effect() const { return m_effect.get(); }
 
 protected:
     virtual void updateChildrenAndEffects(bool) const OVERRIDE { };
     virtual void willDetach() OVERRIDE { };
 
 private:
     InertAnimation(PassRefPtr<AnimationEffect>, const Timing&);
     RefPtr<AnimationEffect> m_effect;
 };
 
 } // namespace WebCore
 
 #endif