Web Animations: Plumb compositor group id through animation creation and start/finish notifications

Source/core/frame/PinchViewport.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 131 matching lines @@
     virtual bool shouldPlaceVerticalScrollbarOnLeft() const override { return false; }
     virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) override;
     virtual void invalidateScrollCornerRect(const IntRect&) override { }
     virtual void setScrollOffset(const IntPoint&) override;
     virtual GraphicsLayer* layerForContainer() const override;
     virtual GraphicsLayer* layerForScrolling() const override;
     virtual GraphicsLayer* layerForHorizontalScrollbar() const override;
     virtual GraphicsLayer* layerForVerticalScrollbar() const override;
 
     // GraphicsLayerClient implementation.
-    virtual void notifyAnimationStarted(const GraphicsLayer*, double monotonicTime) override;
     virtual void paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect& inClip) override;
     virtual String debugName(const GraphicsLayer*) override;
 
     void setupScrollbar(blink::WebScrollbar::Orientation);
     FloatPoint clampOffsetToBoundaries(const FloatPoint&);
     void clampToBoundaries();
 
     LocalFrame* mainFrame() const;
 
     FrameHost& frameHost() const
@@ skipping 14 matching lines @@
 
     // Offset of the pinch viewport from the main frame's origin, in CSS pixels.
     FloatPoint m_offset;
     float m_scale;
     IntSize m_size;
 };
 
 } // namespace blink
 
 #endif // PinchViewport_h