Plumb smooth scrolling in Chromium compositor

cc/layers/layer_impl.h

 // Copyright 2011 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_LAYERS_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 410 matching lines @@
   // them from the other values.
 
   void SetBounds(const gfx::Size& bounds);
   gfx::Size bounds() const;
   // Like bounds() but doesn't snap to int. Lossy on giant pages (e.g. millions
   // of pixels) due to use of single precision float.
   gfx::SizeF BoundsForScrolling() const;
   void SetBoundsDelta(const gfx::Vector2dF& bounds_delta);
   gfx::Vector2dF bounds_delta() const { return bounds_delta_; }
 
-  bool IsExternalScrollActive() const;
-
   void SetCurrentScrollOffset(const gfx::ScrollOffset& scroll_offset);
   void SetCurrentScrollOffsetFromDelegate(
       const gfx::ScrollOffset& scroll_offset);
   void PushScrollOffsetFromMainThread(const gfx::ScrollOffset& scroll_offset);
   // This method is similar to PushScrollOffsetFromMainThread but will cause the
   // scroll offset given to clobber any scroll changes on the active tree in the
   // time until this value is pushed to the active tree.
   void PushScrollOffsetFromMainThreadAndClobberActiveValue(
       const gfx::ScrollOffset& scroll_offset);
   gfx::ScrollOffset PullDeltaForMainThread();
@@ skipping 426 matching lines @@
   bool visited_;
   bool layer_or_descendant_is_drawn_;
   bool sorted_for_recursion_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_