Refactor menu controller to isolate aura dependency.

ui/views/controls/menu/menu_controller.h

Index: ui/views/controls/menu/menu_controller.h
diff --git a/ui/views/controls/menu/menu_controller.h b/ui/views/controls/menu/menu_controller.h
index 5821eec5a312e746e1a99ac8a74f8eb8d1246255..5d8cc7af0f2513b1aedb40b1448c91605aee48c9 100644
--- a/ui/views/controls/menu/menu_controller.h
+++ b/ui/views/controls/menu/menu_controller.h
@@ -37,6 +37,7 @@ namespace views {
 class MenuButton;
 class MenuHostRootView;
 class MenuItemView;
+class MenuMessageLoop;
 class MouseEvent;
 class SubmenuView;
 class View;
@@ -594,7 +595,7 @@ class VIEWS_EXPORT MenuController : public WidgetObserver {
   // Set to true if the menu item was selected by touch.
   bool item_selected_by_touch_;
 
-  scoped_ptr<ui::ScopedEventDispatcher> nested_dispatcher_;
+  scoped_ptr<MenuMessageLoop> message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(MenuController);
 };