Implement a module system for the extension bindings JS.

chrome/renderer/resources/extensions/tabs_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 tabs API.
 
 (function() {
 
-native function GetChromeHidden();
-native function OpenChannelToTab();
+var tabsNatives = requireNative('tabs');
+var OpenChannelToTab = tabsNatives.OpenChannelToTab;
 
-var chromeHidden = GetChromeHidden();
+var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 
 chromeHidden.registerCustomHook('tabs', function(bindingsAPI, extensionId) {
   var apiFunctions = bindingsAPI.apiFunctions;
 
   apiFunctions.setHandleRequest('connect', function(tabId, connectInfo) {
     var name = '';
     if (connectInfo) {
       name = connectInfo.name || name;
     }
     var portId = OpenChannelToTab(tabId, extensionId, name);
@@ skipping 35 matching lines @@
       // If the old signature is used, add a null details object.
       newArgs = [arguments[0], null, arguments[1]];
     } else {
       newArgs = arguments;
     }
     return newArgs;
   });
 });
 
 })();