Refactor extension bindings to share code, avoid exposing hidden variables

chrome/renderer/resources/greasemonkey_api.js

 // Copyright (c) 2009 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.
 
 // -----------------------------------------------------------------------------
 // NOTE: If you change this file you need to touch renderer_resources.grd to
 // have your change take effect.
 // -----------------------------------------------------------------------------
 
 // Implementation of the Greasemonkey API, see:
@@ skipping 115 matching lines @@
   throw new Error("not implemented.");
 }
 
 function GM_openInTab(url) {
   window.open(url, "");
 }
 
 function GM_log(message) {
   window.console.log(message);
 }