Only dispatch menu events if they have a valid target.

ui/views/controls/menu/menu_controller.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_CONTROLS_MENU_MENU_CONTROLLER_H_
 #define UI_VIEWS_CONTROLS_MENU_MENU_CONTROLLER_H_
 
 #include "build/build_config.h"
 
 #include <list>
@@ skipping 73 matching lines @@
                     MenuAnchorPosition position,
                     bool context_menu,
                     int* event_flags);
 
   // Whether or not Run blocks.
   bool IsBlockingRun() const { return blocking_run_; }
 
   // Whether or not drag operation is in progress.
   bool drag_in_progress() const { return drag_in_progress_; }
 
+  // Returns the owner of child windows.
+  // WARNING: this may be NULL.
+  Widget* owner() { return owner_; }
+
   // Get the anchor position wich is used to show this menu.
   MenuAnchorPosition GetAnchorPosition() { return state_.anchor; }
 
   // Cancels the current Run. See ExitType for a description of what happens
   // with the various parameters.
   void Cancel(ExitType type);
 
   // An alternative to Cancel(EXIT_ALL) that can be used with a OneShotTimer.
   void CancelAll() { Cancel(EXIT_ALL); }
 
@@ skipping 495 matching lines @@
   bool item_selected_by_touch_;
 
   scoped_ptr<ui::ScopedEventDispatcher> nested_dispatcher_;
 
   DISALLOW_COPY_AND_ASSIGN(MenuController);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_MENU_MENU_CONTROLLER_H_