Begin to upgrade BackForwardMenuModelViews to use new menu API....

views/controls/menu/menu_2.h

 // Copyright (c) 2009 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 CONTROLS_MENU_VIEWS_MENU_2_H_
 #define CONTROLS_MENU_VIEWS_MENU_2_H_
 
 #include <string>
 
 #include "base/gfx/native_widget_types.h"
@@ skipping 76 matching lines @@
   // Returns the model for the submenu at the specified index.
   virtual Menu2Model* GetSubmenuModelAt(int index) const = 0;
 
   // Called when the highlighted menu item changes to the item at the specified
   // index.
   virtual void HighlightChangedTo(int index) = 0;
 
   // Called when the item at the specified index has been activated.
   virtual void ActivatedAt(int index) = 0;
 
+  // Called when the menu is about to be shown.
+  virtual void MenuWillShow() {}
+
   // Retrieves the model and index that contains a specific command id. Returns
   // true if an item with the specified command id is found. |model| is inout,
   // and specifies the model to start searching from.
   static bool GetModelAndIndexForCommandId(int command_id, Menu2Model** model,
                                            int* index);
 };
 
 // A menu. Populated from a model, and relies on a delegate to execute commands.
 class Menu2 {
  public:
@@ skipping 34 matching lines @@
 
   // The object that actually implements the menu.
   MenuWrapper* wrapper_;
 
   DISALLOW_COPY_AND_ASSIGN(Menu2);
 };
 
 }  // namespace views
 
 #endif  // CONTROLS_MENU_VIEWS_MENU_2_H_