Web Animations: Compositor start notification should only apply to animations in a matching group

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 58 matching lines @@
     Priority priority() const { return m_priority; }
     Element* target() const { return m_target; }
 
     void notifySampledEffectRemovedFromAnimationStack();
 #if !ENABLE(OILPAN)
     void notifyElementDestroyed();
 #endif
 
     bool isCandidateForAnimationOnCompositor(double playerPlaybackRate) const;
     // Must only be called once.
-    bool maybeStartAnimationOnCompositor(double startTime, double timeOffset);
-    bool maybeStartAnimationOnCompositor(double startTime, double timeOffset, double playerPlaybackRate);
+    bool maybeStartAnimationOnCompositor(int group, double startTime, double timeOffset, double playerPlaybackRate);
     bool hasActiveAnimationsOnCompositor() const;
     bool hasActiveAnimationsOnCompositor(CSSPropertyID) const;
     void cancelAnimationOnCompositor();
     void pauseAnimationForTestingOnCompositor(double pauseTime);
 
     virtual void trace(Visitor*) override;
 
     void downgradeToNormalAnimation() { m_priority = DefaultPriority; }
 
 protected:
@@ skipping 17 matching lines @@
     Vector<int> m_compositorAnimationIds;
 
     friend class AnimationAnimationV8Test;
 };
 
 DEFINE_TYPE_CASTS(Animation, AnimationNode, animationNode, animationNode->isAnimation(), animationNode.isAnimation());
 
 } // namespace blink
 
 #endif // Animation_h