Reland of un smooth scroll animations on the compositor when possible

cc/blink/web_compositor_animation_player_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_BLINK_WEB_COMPOSITOR_ANIMATION_PLAYER_IMPL_H_
 #define CC_BLINK_WEB_COMPOSITOR_ANIMATION_PLAYER_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/blink/cc_blink_export.h"
@@ skipping 17 matching lines @@
 
   // blink::WebCompositorAnimationPlayer implementation
   void setAnimationDelegate(
       blink::WebCompositorAnimationDelegate* delegate) override;
   void attachLayer(blink::WebLayer* web_layer) override;
   void detachLayer() override;
   bool isLayerAttached() const override;
   void addAnimation(blink::WebCompositorAnimation* animation) override;
   void removeAnimation(int animation_id) override;
   void pauseAnimation(int animation_id, double time_offset) override;
+  void abortAnimation(int animation_id) override;
 
  private:
   scoped_refptr<cc::AnimationPlayer> animation_player_;
   scoped_ptr<WebToCCAnimationDelegateAdapter> animation_delegate_adapter_;
 
   DISALLOW_COPY_AND_ASSIGN(WebCompositorAnimationPlayerImpl);
 };
 
 }  // namespace cc_blink
 
 #endif  // CC_BLINK_WEB_COMPOSITOR_ANIMATION_PLAYER_IMPL_H_