Plumb PinchVirtualViewport layers into CC.

content/renderer/gpu/render_widget_compositor.h

Index: content/renderer/gpu/render_widget_compositor.h
diff --git a/content/renderer/gpu/render_widget_compositor.h b/content/renderer/gpu/render_widget_compositor.h
index 37b66dabed8ab00a35b3ebda1b277127428866b3..c8e127ddaa87f484ba7d47ed7738d58f401aa681 100644
--- a/content/renderer/gpu/render_widget_compositor.h
+++ b/content/renderer/gpu/render_widget_compositor.h
@@ -87,6 +87,12 @@ class RenderWidgetCompositor : public WebKit::WebLayerTreeView,
   virtual void finishAllRendering();
   virtual void setDeferCommits(bool defer_commits);
   virtual void registerForAnimations(WebKit::WebLayer* layer);
+  virtual void registerPinchViewportLayers(
+      const WebKit::WebLayer* innerViewportClipLayer,
+      const WebKit::WebLayer* pageScaleLayer,
+      const WebKit::WebLayer* innerViewportScrollLayer,
+      const WebKit::WebLayer* outerViewportScrollLayer) OVERRIDE;
+  virtual void clearPinchViewportLayers() OVERRIDE;
   virtual void renderingStats(WebKit::WebRenderingStats& stats) const {}
   virtual void setShowFPSCounter(bool show);
   virtual void setShowPaintRects(bool show);