Revert "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 9464d9541bf09f9f4a40e7436e47caae2da70918..de59c127cf8a3569088be1313bdcf2464e158225 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -118,10 +118,6 @@ class CC_EXPORT LayerTreeImpl {
 
   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();
   void ApplySentScrollAndScaleDeltasFromAbortedCommit();
   void ApplyScrollDeltasSinceBeginFrame();
 
@@ -231,10 +227,6 @@ 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_;