Implement a module system for the extension bindings JS.

chrome/renderer/resources/extensions/context_menus_custom_bindings.js

 // Copyright (c) 2012 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.
 
 // Custom bindings for the contextMenus API.
 
-(function() {
-
-native function GetChromeHidden();
-native function GetNextContextMenuId();
+var GetChromeHidden = natives.GetChromeHidden;
+var GetNextContextMenuId = natives.GetNextContextMenuId;
 
 var chromeHidden = GetChromeHidden();
 
 chromeHidden.registerCustomHook('contextMenus', function(bindingsAPI) {
   var apiFunctions = bindingsAPI.apiFunctions;
   var sendRequest = bindingsAPI.sendRequest;
 
   chromeHidden.contextMenus = {};
   chromeHidden.contextMenus.handlers = {};
   var eventName = "contextMenus";
@@ skipping 62 matching lines @@
   });
 
   apiFunctions.setCustomCallback("contextMenus.removeAll",
       function(name, request, response) {
     if (chrome.extension.lastError) {
       return;
     }
     chromeHidden.contextMenus.handlers = {};
   });
 });
-
-})();