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

app/menus/button_menu_item_model.cc

 // 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.
 
 #include "app/menus/button_menu_item_model.h"
 
 #include "app/l10n_util.h"
 
 namespace menus {
 
@@ skipping 84 matching lines @@
 
 bool ButtonMenuItemModel::PartOfGroup(int index) const {
   return items_[index].part_of_group;
 }
 
 void ButtonMenuItemModel::ActivatedCommand(int command_id) {
   if (delegate_)
     delegate_->ExecuteCommand(command_id);
 }
 
+bool ButtonMenuItemModel::IsEnabledAt(int index) const {
+  if (delegate_)
+    return delegate_->IsCommandIdEnabled(items_[index].command_id);
+  return true;
+}
+
 }  // namespace menus