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

Source/core/frame/PinchViewport.cpp

Index: Source/core/frame/PinchViewport.cpp
diff --git a/Source/core/frame/PinchViewport.cpp b/Source/core/frame/PinchViewport.cpp
index 2c1bc055f5171ea4af3b7277212afb360887dc45..ed95f46d1276c3eb9921b2b2034a4c10efa5631d 100644
--- a/Source/core/frame/PinchViewport.cpp
+++ b/Source/core/frame/PinchViewport.cpp
@@ -444,10 +444,6 @@ GraphicsLayer* PinchViewport::layerForVerticalScrollbar() const
     return m_overlayScrollbarVertical.get();
 }
 
-void PinchViewport::notifyAnimationStarted(const GraphicsLayer*, double monotonicTime)
-{
-}
-
 void PinchViewport::paintContents(const GraphicsLayer*, GraphicsContext&, GraphicsLayerPaintingPhase, const IntRect& inClip)
 {
 }