Plumb smooth scrolling in Chromium compositor

cc/trees/layer_tree_impl.h

 // Copyright 2012 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_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 322 matching lines @@
   void set_top_controls_height(float top_controls_height);
   float top_controls_height() const { return top_controls_height_; }
   void PushTopControlsFromMainThread(float top_controls_shown_ratio);
 
   void SetPendingPageScaleAnimation(
       scoped_ptr<PendingPageScaleAnimation> pending_animation);
   scoped_ptr<PendingPageScaleAnimation> TakePendingPageScaleAnimation();
 
   void GatherFrameTimingRequestIds(std::vector<int64_t>* request_ids);
 
-  bool IsExternalScrollActive() const;
   void DidUpdateScrollOffset(int layer_id);
 
   bool IsAnimatingFilterProperty(const LayerImpl* layer) const;
   bool IsAnimatingOpacityProperty(const LayerImpl* layer) const;
   bool IsAnimatingTransformProperty(const LayerImpl* layer) const;
 
   bool HasPotentiallyRunningFilterAnimation(const LayerImpl* layer) const;
   bool HasPotentiallyRunningOpacityAnimation(const LayerImpl* layer) const;
   bool HasPotentiallyRunningTransformAnimation(const LayerImpl* layer) const;
 
@@ skipping 100 matching lines @@
 
   scoped_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_