Turn RootWindowController Menus Async

ash/root_window_controller.h

Index: ash/root_window_controller.h
diff --git a/ash/root_window_controller.h b/ash/root_window_controller.h
index e37ec6c2aa9fb5bb190feb69e8dfe8fad7742d3a..d5caa0c3fc2b3576aeb971d3d1b1bf828858354a 100644
--- a/ash/root_window_controller.h
+++ b/ash/root_window_controller.h
@@ -34,9 +34,12 @@ class KeyboardController;
 
 namespace ui {
 class EventHandler;
+class MenuModel;
 }
 
 namespace views {
+class MenuModelAdapter;
+class MenuRunner;
 class Widget;
 }
 
@@ -257,6 +260,9 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
   // Disables projection touch HUD.
   void DisableTouchHudProjection();
 
+  // Callback for MenuModelAdapter.
+  void OnMenuClosed();
+
   // Overridden from ShellObserver.
   void OnLoginStateChanged(user::LoginStatus status) override;
   void OnTouchHudProjectionToggled(bool enabled) override;
@@ -306,6 +312,11 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
   std::unique_ptr<AnimatingDesktopController> animating_wallpaper_controller_;
   std::unique_ptr<::wm::ScopedCaptureClient> capture_client_;
 
+  // Manages the context menu.
+  std::unique_ptr<ui::MenuModel> menu_model_;
+  std::unique_ptr<views::MenuModelAdapter> menu_model_adapter_;
+  std::unique_ptr<views::MenuRunner> menu_runner_;
+
   DISALLOW_COPY_AND_ASSIGN(RootWindowController);
 };