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

cc/layers/layer.h

 // Copyright 2010 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_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 233 matching lines @@
   void SetNonFastScrollableRegion(const Region& non_fast_scrollable_region);
   const Region& non_fast_scrollable_region() const {
     return inputs_.non_fast_scrollable_region;
   }
 
   void SetTouchEventHandlerRegion(const Region& touch_event_handler_region);
   const Region& touch_event_handler_region() const {
     return inputs_.touch_event_handler_region;
   }
 
-  void set_did_scroll_callback(const base::Closure& callback) {
+  void set_did_scroll_callback(
+      const base::Callback<void(const gfx::ScrollOffset&)>& callback) {
     inputs_.did_scroll_callback = callback;
   }
 
   void SetForceRenderSurfaceForTesting(bool force_render_surface);
   bool force_render_surface_for_testing() const {
     return force_render_surface_for_testing_;
   }
 
   gfx::ScrollOffset CurrentScrollOffset() const {
     return inputs_.scroll_offset;
@@ skipping 342 matching lines @@
     Layer* scroll_parent;
     Layer* clip_parent;
 
     bool has_will_change_transform_hint : 1;
     bool has_preferred_raster_bounds : 1;
 
     bool hide_layer_and_subtree : 1;
 
     // The following elements can not and are not serialized.
     LayerClient* client;
-    base::Closure did_scroll_callback;
+    base::Callback<void(const gfx::ScrollOffset&)> did_scroll_callback;
     std::vector<std::unique_ptr<CopyOutputRequest>> copy_requests;
 
     gfx::Size preferred_raster_bounds;
   };
 
   Layer* parent_;
 
   // Layer instances have a weak pointer to their LayerTreeHost.
   // This pointer value is nil when a Layer is not in a tree and is
   // updated via SetLayerTreeHost() if a layer moves between trees.
@@ skipping 28 matching lines @@
   // These all act like draw properties, so don't need push properties.
   gfx::Rect visible_layer_rect_;
   size_t num_unclipped_descendants_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_