Update from https://crrev.com/305340

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 <list>
 #include <set>
 #include <string>
@@ skipping 26 matching lines @@
 class LayerTreeSettings;
 class MemoryHistory;
 class OutputSurface;
 class PageScaleAnimation;
 class PaintTimeCounter;
 class PictureLayerImpl;
 class Proxy;
 class ResourceProvider;
 class TileManager;
 class UIResourceRequest;
+struct PendingPageScaleAnimation;
 struct RendererCapabilities;
 struct SelectionHandle;
 
 typedef std::list<UIResourceRequest> UIResourceRequestQueue;
 
 class CC_EXPORT LayerTreeImpl {
  public:
   static scoped_ptr<LayerTreeImpl> create(
       LayerTreeHostImpl* layer_tree_host_impl) {
     return make_scoped_ptr(new LayerTreeImpl(layer_tree_host_impl));
@@ skipping 73 matching lines @@
   gfx::ScrollOffset TotalScrollOffset() const;
   gfx::ScrollOffset TotalMaxScrollOffset() const;
   gfx::Vector2dF TotalScrollDelta() const;
 
   LayerImpl* InnerViewportContainerLayer() const;
   LayerImpl* OuterViewportContainerLayer() const;
   LayerImpl* CurrentlyScrollingLayer() const;
   void SetCurrentlyScrollingLayer(LayerImpl* layer);
   void ClearCurrentlyScrollingLayer();
 
-  void SetViewportLayersFromIds(int page_scale_layer_id,
+  void SetViewportLayersFromIds(int overscroll_elasticity_layer,
+                                int page_scale_layer_id,
                                 int inner_viewport_scroll_layer_id,
                                 int outer_viewport_scroll_layer_id);
   void ClearViewportLayers();
+  LayerImpl* overscroll_elasticity_layer() {
+    return overscroll_elasticity_layer_;
+  }
   LayerImpl* page_scale_layer() { return page_scale_layer_; }
   void ApplySentScrollAndScaleDeltasFromAbortedCommit();
   void ApplyScrollDeltasSinceBeginMainFrame();
 
   SkColor background_color() const { return background_color_; }
   void set_background_color(SkColor color) { background_color_ = color; }
 
   bool has_transparent_background() const {
     return has_transparent_background_;
   }
@@ skipping 149 matching lines @@
   float top_controls_delta() const {
     return top_controls_delta_;
   }
   float sent_top_controls_delta() const {
     return sent_top_controls_delta_;
   }
   float total_top_controls_content_offset() const {
     return top_controls_content_offset_ + top_controls_delta_;
   }
 
-  void SetPageScaleAnimation(
-      const gfx::Vector2d& target_offset,
-      bool anchor_point,
-      float page_scale,
-      base::TimeDelta duration);
-  scoped_ptr<PageScaleAnimation> TakePageScaleAnimation();
+  void SetPendingPageScaleAnimation(
+      scoped_ptr<PendingPageScaleAnimation> pending_animation);
+  scoped_ptr<PendingPageScaleAnimation> TakePendingPageScaleAnimation();
 
  protected:
   explicit LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl);
   void ReleaseResourcesRecursive(LayerImpl* current);
 
   LayerTreeHostImpl* layer_tree_host_impl_;
   int source_frame_number_;
   scoped_ptr<LayerImpl> root_layer_;
   HeadsUpDisplayLayerImpl* hud_layer_;
   LayerImpl* currently_scrolling_layer_;
   LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate_;
   scoped_ptr<LayerScrollOffsetDelegateProxy>
       inner_viewport_scroll_delegate_proxy_;
   scoped_ptr<LayerScrollOffsetDelegateProxy>
       outer_viewport_scroll_delegate_proxy_;
   SkColor background_color_;
   bool has_transparent_background_;
 
+  LayerImpl* overscroll_elasticity_layer_;
   LayerImpl* page_scale_layer_;
   LayerImpl* inner_viewport_scroll_layer_;
   LayerImpl* outer_viewport_scroll_layer_;
 
   LayerSelectionBound selection_start_;
   LayerSelectionBound selection_end_;
 
   float page_scale_factor_;
   float page_scale_delta_;
   float sent_page_scale_delta_;
@@ skipping 33 matching lines @@
   // viewport resize) in Blink. i.e. How much the viewport was shrunk by the top
   // controls.
   float top_controls_layout_height_;
 
   // The up-to-date content offset of the top controls, i.e. the amount that the
   // web contents have been shifted down from the top of the device viewport.
   float top_controls_content_offset_;
   float top_controls_delta_;
   float sent_top_controls_delta_;
 
-  scoped_ptr<PageScaleAnimation> page_scale_animation_;
+  scoped_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_