Refactor delegated scrolling in LayerImpl

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index b13dce911a61eeac191d853027b8edfd841c8595..e708cdd4b4c46b959413634a14e2603af5a3b6d3 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -80,16 +80,6 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
                             public LayerAnimationValueProvider,
                             public AnimationDelegate {
  public:
-  // Allows for the ownership of the total scroll offset to be delegated outside
-  // of the layer.
-  class ScrollOffsetDelegate {
-   public:
-    virtual void SetCurrentScrollOffset(const gfx::ScrollOffset& new_value) = 0;
-    virtual gfx::ScrollOffset GetCurrentScrollOffset() = 0;
-    virtual bool IsExternalFlingActive() const = 0;
-    virtual void Update() const = 0;
-  };
-
   typedef SyncedProperty<AdditionGroup<gfx::ScrollOffset>> SyncedScrollOffset;
   typedef LayerImplList RenderSurfaceListType;
   typedef LayerImplList LayerListType;
@@ -390,8 +380,6 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
   float contents_scale_y() const { return draw_properties_.contents_scale_y; }
   void SetContentsScale(float contents_scale_x, float contents_scale_y);
 
-  void SetScrollOffsetDelegate(ScrollOffsetDelegate* scroll_offset_delegate);
-  void RefreshFromScrollDelegate();
   bool IsExternalFlingActive() const;
 
   void SetCurrentScrollOffset(const gfx::ScrollOffset& scroll_offset);
@@ -672,7 +660,6 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
   // Properties synchronized from the associated Layer.
   gfx::Point3F transform_origin_;
   gfx::Size bounds_;
-  ScrollOffsetDelegate* scroll_offset_delegate_;
   LayerImpl* scroll_clip_layer_;
   bool scrollable_ : 1;
   bool should_scroll_on_main_thread_ : 1;