Pinch/Zoom Infrastructure & Plumbing CL

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index fa7660299a68e8bd52b401d6f09bc98cd69e4a80..fe83af5d2e18c7eef20998e0b7989f4d1570d733 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -279,7 +279,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   // Shortcuts to layers on the active tree.
   LayerImpl* RootLayer() const;
-  LayerImpl* RootScrollLayer() const;
+  LayerImpl* InnerViewportScrollLayer() const;
+  LayerImpl* OuterViewportScrollLayer() const;
   LayerImpl* CurrentlyScrollingLayer() const;
 
   int scroll_layer_id_when_mouse_over_scrollbar() {
@@ -466,6 +467,7 @@ class CC_EXPORT LayerTreeHostImpl
   void ReleaseTreeResources();
   void EnforceZeroBudget(bool zero_budget);
 
+  void ScrollViewportBy(gfx::Vector2dF scroll_delta);
   void AnimatePageScale(base::TimeTicks monotonic_time);
   void AnimateScrollbars(base::TimeTicks monotonic_time);
   void AnimateTopControls(base::TimeTicks monotonic_time);
@@ -476,7 +478,6 @@ class CC_EXPORT LayerTreeHostImpl
       const gfx::PointF& viewport_point,
       const gfx::Vector2dF& viewport_delta);
 
-  void UpdateMaxScrollOffset();
   void TrackDamageForAllSurfaces(
       LayerImpl* root_draw_layer,
       const LayerImplList& render_surface_layer_list);