Pinch/Zoom Infrastructure & Plumbing CL

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 76e6d53edb95b7ebacd9335b70a4b4054138a515..21e3f2c7cf700906f8c3e0d5d7d35926e8492166 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -110,18 +110,23 @@ class CC_EXPORT LayerTreeImpl {
     hud_layer_ = layer_impl;
   }
 
-  LayerImpl* RootScrollLayer() const;
+  LayerImpl* InnerViewportScrollLayer() const;
+  // This function may return NULL, it is the caller's responsibility to check.
+  LayerImpl* OuterViewportScrollLayer() const;
+  gfx::Vector2dF TotalScrollOffset() const;
+  gfx::Vector2dF TotalMaxScrollOffset() const;
+  gfx::Vector2dF TotalScrollDelta() const;
+
   LayerImpl* RootContainerLayer() const;
   LayerImpl* CurrentlyScrollingLayer() const;
   void SetCurrentlyScrollingLayer(LayerImpl* layer);
   void ClearCurrentlyScrollingLayer();
 
-  void FindRootScrollLayer();
-  void UpdateMaxScrollOffset();
   void SetViewportLayersFromIds(int page_scale_layer_id,
                                 int inner_viewport_scroll_layer_id,
                                 int outer_viewport_scroll_layer_id);
   void ClearViewportLayers();
+  LayerImpl* page_scale_layer() { return page_scale_layer_; }
   void ApplySentScrollAndScaleDeltasFromAbortedCommit();
   void ApplyScrollDeltasSinceBeginMainFrame();
 
@@ -219,15 +224,12 @@ class CC_EXPORT LayerTreeImpl {
  protected:
   explicit LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl);
 
-  void UpdateSolidColorScrollbars();
-
   void UpdateRootScrollLayerSizeDelta();
 
   LayerTreeHostImpl* layer_tree_host_impl_;
   int source_frame_number_;
   scoped_ptr<LayerImpl> root_layer_;
   HeadsUpDisplayLayerImpl* hud_layer_;
-  LayerImpl* root_scroll_layer_;
   LayerImpl* currently_scrolling_layer_;
   LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate_;
   SkColor background_color_;