Remove GraphicsLayer::didScroll and directly call ScrollableArea::didScroll

ui/compositor/layer.h

Index: ui/compositor/layer.h
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index e1525b572869886b14383621bd6a97b99c4c2434..76451c0a8300f4e3dfbaa84c164dd159696ffb69 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -349,7 +349,9 @@ class COMPOSITOR_EXPORT Layer
 
   // Makes this Layer scrollable, clipping to |parent_clip_layer|. |on_scroll|
   // is invoked when scrolling performed by the cc::InputHandler is committed.
-  void SetScrollable(Layer* parent_clip_layer, const base::Closure& on_scroll);
+  void SetScrollable(
+      Layer* parent_clip_layer,
+      const base::Callback<void(const gfx::ScrollOffset&)>& on_scroll);
 
   // Gets and sets the current scroll offset of the layer.
   gfx::ScrollOffset CurrentScrollOffset() const;