Plumb PinchVirtualViewport layers into CC.

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 969cba2d0756a3e77da8749175dd4c02d51abf1a..33a8f94bf46e42b2159a5ce25b8f6cf0ec728112 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -118,6 +118,9 @@ class CC_EXPORT LayerTreeImpl {
 
   void FindRootScrollLayer();
   void UpdateMaxScrollOffset();
+  void SetPinchViewportLayerIds(int page_scale_layer_id,

[enne (OOO), 2013/09/11 20:13:03]

bikeshed: s/Pinch// to match the LTH functions?

[wjmaclean, 2013/09/12 18:16:47]

Done.

Definitely! :-)

+                                int inner_viewport_scroll_layer_id,
+                                int outer_viewport_scroll_layer_id);
   void ApplySentScrollAndScaleDeltasFromAbortedCommit();
   void ApplyScrollDeltasSinceBeginFrame();
 
@@ -227,6 +230,10 @@ class CC_EXPORT LayerTreeImpl {
   SkColor background_color_;
   bool has_transparent_background_;
 
+  LayerImpl* page_scale_layer_;
+  LayerImpl* inner_viewport_scroll_layer_;
+  LayerImpl* outer_viewport_scroll_layer_;
+
   float page_scale_factor_;
   float page_scale_delta_;
   float sent_page_scale_delta_;