Run CSSOM smooth scroll animations on the compositor when possible

Source/platform/graphics/GraphicsLayer.cpp

 /*
  * Copyright (C) 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1067 matching lines @@
     paintGraphicsLayerContents(context, clip);
 }
 
 
 void GraphicsLayer::notifyAnimationStarted(double monotonicTime, int group)
 {
     if (m_client)
         m_client->notifyAnimationStarted(this, monotonicTime, group);
 }
 
-void GraphicsLayer::notifyAnimationFinished(double, int)
+void GraphicsLayer::notifyAnimationFinished(double, int group)
 {
+    if (m_scrollableArea)
+        m_scrollableArea->notifyCompositorAnimationFinished(group);
 }
 
 void GraphicsLayer::didScroll()
 {
     if (m_scrollableArea) {
         DoublePoint newPosition = m_scrollableArea->minimumScrollPosition() + toDoubleSize(m_layer->layer()->scrollPositionDouble());
+        bool cancelProgrammaticAnimations = false;
         // FIXME: Remove the toFloatPoint(). crbug.com/414283.
-        m_scrollableArea->scrollToOffsetWithoutAnimation(toFloatPoint(newPosition));
+        m_scrollableArea->scrollToOffsetWithoutAnimation(toFloatPoint(newPosition), cancelProgrammaticAnimations);
     }
 }
 
 DisplayItemList* GraphicsLayer::displayItemList()
 {
     if (!RuntimeEnabledFeatures::slimmingPaintEnabled())
         return 0;
     if (!m_displayItemList)
         m_displayItemList = DisplayItemList::create();
     return m_displayItemList.get();
 }
 
 } // namespace blink
 
 #ifndef NDEBUG
 void showGraphicsLayerTree(const blink::GraphicsLayer* layer)
 {
     if (!layer)
         return;
 
     String output = layer->layerTreeAsText(blink::LayerTreeIncludesDebugInfo);
     fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif