Pinch/Zoom Infrastructure & Plumbing CL

cc/trees/layer_tree_host.h

Index: cc/trees/layer_tree_host.h
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index 867bb197caf29fcea3537656c958fc85f615ad14..77e2046c7c892b44e34c859723066bec6564479d 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -97,6 +97,7 @@ class CC_EXPORT LayerTreeHost {
       const LayerTreeSettings& settings);
   virtual ~LayerTreeHost();
 
+  const Layer* LayerById(const int id) const;
   void SetLayerTreeHostClientReady();
 
   void set_needs_filter_context() { needs_filter_context_ = true; }
@@ -195,6 +196,12 @@ class CC_EXPORT LayerTreeHost {
       scoped_refptr<Layer> page_scale_layer,
       scoped_refptr<Layer> inner_viewport_scroll_layer,
       scoped_refptr<Layer> outer_viewport_scroll_layer);
+  Layer* inner_viewport_scroll_layer() const {
+    return inner_viewport_scroll_layer_.get();
+  }
+  Layer* outer_viewport_scroll_layer() const {
+    return outer_viewport_scroll_layer_.get();
+  }
 
   const LayerTreeSettings& settings() const { return settings_; }
 
@@ -235,6 +242,8 @@ class CC_EXPORT LayerTreeHost {
                                base::TimeDelta duration);
 
   void ApplyScrollAndScale(const ScrollAndScaleSet& info);
+  gfx::Vector2d DistributeScrollOffsetToViewports(const gfx::Vector2d offset,
+                                                  Layer* layer);
 
   void SetImplTransform(const gfx::Transform& transform);