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

Source/core/animation/AnimationPlayer.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 125 matching lines @@
 
     bool canStartAnimationOnCompositor();
     bool maybeStartAnimationOnCompositor();
     void cancelAnimationOnCompositor();
     bool hasActiveAnimationsOnCompositor();
     void setCompositorPending(bool sourceChanged = false);
     void notifyCompositorStartTime(double timelineTime);
     void notifyStartTime(double timelineTime);
 
 
-    void preCommit(bool startOnCompositor);
+    void preCommit(int compositorGroup, bool startOnCompositor);
     void postCommit(double timelineTime);
 
     unsigned sequenceNumber() const { return m_sequenceNumber; }
+    int compositorGroup() const { return m_compositorGroup; }
 
     static bool hasLowerPriority(AnimationPlayer* player1, AnimationPlayer* player2)
     {
         return player1->sequenceNumber() < player2->sequenceNumber();
     }
 
 #if !ENABLE(OILPAN)
     // Checks if the AnimationStack is the last reference holder to the Player.
     // This won't be needed when AnimationPlayer is moved to Oilpan.
     bool canFree() const;
@@ skipping 80 matching lines @@
         AnimationPlayer& m_player;
         AnimationPlayState m_initial;
         CompositorPendingChange m_compositorPendingChange;
     };
 
     // This mirrors the known compositor state. It is created when a compositor
     // animation is started. Updated once the start time is known and each time
     // modifications are pushed to the compositor.
     OwnPtr<CompositorState> m_compositorState;
     bool m_compositorPending;
+    int m_compositorGroup;
+
     bool m_currentTimePending;
 };
 
 } // namespace blink
 
 #endif // AnimationPlayer_h