Fix RenderWidgetHostViewAura as observer of CompositorVSyncManager

content/browser/renderer_host/render_widget_host_view_aura.h

Index: content/browser/renderer_host/render_widget_host_view_aura.h
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.h b/content/browser/renderer_host/render_widget_host_view_aura.h
index 7c6605cc62ccf2478f9cdf9c8ca0c1db897066db..aa3a80f1e76d13458859ecf76cb576b31b5d0cfc 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -62,6 +62,7 @@ class Display;
 
 namespace ui {
 class CompositorLock;
+class CompositorVSyncManager;
 class InputMethod;
 class LocatedEvent;
 class Texture;
@@ -640,6 +641,9 @@ class CONTENT_EXPORT RenderWidgetHostViewAura
   // This holds the current software framebuffer, if any.
   scoped_ptr<SoftwareFrameManager> software_frame_manager_;
 
+  // The vsync manager we are observing for changes, if any.
+  scoped_refptr<ui::CompositorVSyncManager> vsync_manager_;
+
   // With delegated renderer, this is the last output surface, used to
   // disambiguate resources with the same id coming from different output
   // surfaces.