The button menu items on GTK menus honor the enabled state of the command....

app/menus/button_menu_item_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_BUTTON_MENU_ITEM_MODEL_H_
 #define APP_MENUS_BUTTON_MENU_ITEM_MODEL_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 66 matching lines @@
   // If the button at |index| should have its size equalized along with all
   // other items that have their PartOfGroup bit set.
   bool PartOfGroup(int index) const;
 
   // Called from implementations.
   void ActivatedCommand(int command_id);
 
   // Returns the enabled state of the button at |index|.
   bool IsEnabledAt(int index) const;
 
+  // Returns the enabled state of the command specified by |command_id|.
+  bool IsCommandIdEnabled(int command_id) const;
+
   const string16& label() const { return item_label_; }
 
  private:
   // The non-clickable label to the left of the buttons.
   string16 item_label_;
 
   struct Item;
   std::vector<Item> items_;
 
   Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ButtonMenuItemModel);
 };
 
 }  // namespace menus
 
 #endif  // APP_MENUS_BUTTON_MENU_ITEM_MODEL_H_