Make the chrome.webstore bindings load lazily.

chrome/renderer/resources/extensions/webstore_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 webstore API.
 
-var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 var webstoreNatives = requireNative('webstore');
 
 function Installer() {
   this._pendingInstalls = {};
 }
 
 Installer.prototype.install = function(url, onSuccess, onFailure) {
   var installId = webstoreNatives.Install(url, onSuccess, onFailure);
   if (installId !== undefined) {
     if (installId in this._pendingInstalls)
@@ skipping 17 matching lines @@
       pendingInstall.onSuccess();
     else if (!success && pendingInstall.onFailure)
       pendingInstall.onFailure(error);
   } finally {
     delete this._pendingInstalls[installId];
   }
 };
 
 var installer = new Installer();
 
-chrome.webstore = {
+var chromeWebstore = {
   install: function install(url, onSuccess, onFailure) {
     installer.install(url, onSuccess, onFailure);
   }
 };
 
 // Called by webstore_bindings.cc.
-chromeHidden.webstore = {
+var chromeHiddenWebstore = {
   onInstallResponse: function(installId, success, error) {
     installer.onInstallResponse(installId, success, error);
   }
 };
+
+exports.chromeWebstore = chromeWebstore;
+exports.chromeHiddenWebstore = chromeHiddenWebstore;