The "Update Chrome" menu item should appear in addition to the About menu.

app/menus/menu_model.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 APP_MENUS_MENU_MODEL_H_
 #define APP_MENUS_MENU_MODEL_H_
 #pragma once
 
 #include "base/scoped_ptr.h"
 #include "base/string16.h"
@@ skipping 76 matching lines @@
   // Gets the icon for the item at the specified index, returning true if there
   // is an icon, false otherwise.
   virtual bool GetIconAt(int index, SkBitmap* icon) const = 0;
 
   // Returns the model for a menu item with a line of buttons at |index|.
   virtual ButtonMenuItemModel* GetButtonMenuItemAt(int index) const = 0;
 
   // Returns the enabled state of the item at the specified index.
   virtual bool IsEnabledAt(int index) const = 0;
 
+  // Returns true if the menu item is visible.
+  virtual bool IsVisibleAt(int index) const;
+
   // Returns the model for the submenu at the specified index.
   virtual MenuModel* 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, MenuModel** model,
                                            int* index);
 };
 
 }  // namespace
 
 #endif  // APP_MENUS_MENU_MODEL_H_