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

app/menus/simple_menu_model.h

 // Copyright (c) 2010 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_SIMPLE_MENU_MODEL_H_
 #define APP_MENUS_SIMPLE_MENU_MODEL_H_
 #pragma once
 
 #include <vector>
 
 #include "base/string16.h"
 #include "app/menus/menu_model.h"
 
 namespace menus {
 
 class ButtonMenuItemModel;
 
 // A simple MenuModel implementation with an imperative API for adding menu
 // items. This makes it easy to construct fixed menus. Menus populated by
 // dynamic data sources may be better off implementing MenuModel directly.
 // The breadth of MenuModel is not exposed through this API.
 class SimpleMenuModel : public MenuModel {
  public:
   class Delegate {
    public:
     // Methods for determining the state of specific command ids.
     virtual bool IsCommandIdChecked(int command_id) const = 0;
     virtual bool IsCommandIdEnabled(int command_id) const = 0;
+    virtual bool IsCommandIdVisible(int command_id) const;
 
     // Gets the accelerator for the specified command id. Returns true if the
     // command id has a valid accelerator, false otherwise.
     virtual bool GetAcceleratorForCommandId(
         int command_id,
         menus::Accelerator* accelerator) = 0;
 
     // Some command ids have labels that change over time.
     virtual bool IsLabelForCommandIdDynamic(int command_id) const;
     virtual string16 GetLabelForCommandId(int command_id) const;
@@ skipping 61 matching lines @@
   virtual int GetCommandIdAt(int index) const;
   virtual string16 GetLabelAt(int index) const;
   virtual bool IsLabelDynamicAt(int index) const;
   virtual bool GetAcceleratorAt(int index,
                                 menus::Accelerator* accelerator) const;
   virtual bool IsItemCheckedAt(int index) const;
   virtual int GetGroupIdAt(int index) const;
   virtual bool GetIconAt(int index, SkBitmap* icon) const;
   virtual menus::ButtonMenuItemModel* GetButtonMenuItemAt(int index) const;
   virtual bool IsEnabledAt(int index) const;
+  virtual bool IsVisibleAt(int index) const;
   virtual void HighlightChangedTo(int index);
   virtual void ActivatedAt(int index);
   virtual MenuModel* GetSubmenuModelAt(int index) const;
 
  protected:
   // Some variants of this model (SystemMenuModel) relies on items to be
   // inserted backwards. This is counter-intuitive for the API, so rather than
   // forcing customers to insert things backwards, we return the indices
   // backwards instead. That's what this method is for. By default, it just
   // returns what it's passed.
-  virtual int FlipIndex(int index) const { return index; }
+  virtual int FlipIndex(int index) const;
 
   Delegate* delegate() { return delegate_; }
 
  private:
   struct Item;
   std::vector<Item> items_;
 
   // Functions for inserting items into |items_|.
   void AppendItem(const Item& item);
   void InsertItemAtIndex(const Item& item, int index);
   void ValidateItem(const Item& item);
 
   Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(SimpleMenuModel);
 };
 
 }  // namespace menus
 
 #endif  // APP_MENUS_SIMPLE_MENU_MODEL_H_