[Extensions Bindings] Add a messaging test

extensions/renderer/resources/runtime_custom_bindings.js

 // Copyright 2014 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 binding for the runtime API.
 
-var binding = require('binding').Binding.create('runtime');
+var binding = apiBridge || require('binding').Binding.create('runtime');
 
 var messaging = require('messaging');
 var runtimeNatives = requireNative('runtime');
 var messagingNatives = requireNative('messaging_natives');
 var process = requireNative('process');
 var utils = require('utils');
 
 var WINDOW = {};
 try {
   WINDOW = window;
@@ skipping 163 matching lines @@
       var bg =
           runtimeNatives.GetExtensionViews(-1, -1, 'BACKGROUND')[0] || null;
       callback(bg);
     }
   });
 
   bindDirectoryEntryCallback('getPackageDirectoryEntry', apiFunctions);
 });
 
 exports.$set('bindDirectoryEntryCallback', bindDirectoryEntryCallback);
-exports.$set('binding', binding.generate());
+if (!apiBridge)
+  exports.$set('binding', binding.generate());