The Mac wrench menu zoom controls honor the global enabled state of the zoom commands.

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 13 matching lines @@
   };
 
   class Delegate {
    public:
     // Some command ids have labels that change over time.
     virtual bool IsLabelForCommandIdDynamic(int command_id) const;
     virtual string16 GetLabelForCommandId(int command_id) const;
 
     // Performs the action associated with the specified command id.
     virtual void ExecuteCommand(int command_id) = 0;
+    virtual bool IsCommandIdEnabled(int command_id) const { return true; }
   };
 
   ButtonMenuItemModel(int string_id, ButtonMenuItemModel::Delegate* delegate);
   ~ButtonMenuItemModel();
 
   // Adds a button that will emit |command_id|. All buttons created through
   // this method will have the same size, based on the largest button.
   void AddGroupItemWithStringId(int command_id, int string_id);
 
   // Adds a button that has an icon instead of a label.
@@ skipping 26 matching lines @@
   // sets the IDR |icon|.
   bool GetIconAt(int index, int* icon) const;
 
   // 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;
+
   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_