Implement a module system for the extension bindings JS.

chrome/renderer/resources/extensions/storage_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 storage API.
 
-(function() {
-
-native function GetChromeHidden();
-
-var chromeHidden = GetChromeHidden();
+var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 
 chromeHidden.registerCustomType('StorageArea', function(typesAPI) {
   var sendRequest = typesAPI.sendRequest;
 
   function extendSchema(schema) {
     var extendedSchema = schema.slice();
     extendedSchema.unshift({'type': 'string'});
     return extendedSchema;
   }
 
@@ skipping 14 matching lines @@
             [namespace].concat(Array.prototype.slice.call(arguments)),
             extendSchema(schema));
       };
     }
     var apiFunctions = ['get', 'set', 'remove', 'clear', 'getBytesInUse'];
     apiFunctions.forEach(bindApiFunction.bind(this));
   }
 
   return StorageArea;
 });
-
-})();