Make 'options' and callback arg to chrome.appWindow.create optional.

chrome/renderer/resources/extensions/app_window_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 app_window API.
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 var sendRequest = require('sendRequest').sendRequest;
 var appWindowNatives = requireNative('app_window');
+var GetView = appWindowNatives.GetView;
 
-chromeHidden.registerCustomHook('appWindow', function() {
-  var internal_appWindow_create = chrome.appWindow.create;
-  chrome.appWindow.create = function(url, opts, cb) {
-    internal_appWindow_create(url, opts, function(view_id) {
-      var dom = appWindowNatives.GetView(view_id);
-      cb(dom);
-    });
-  };
+chromeHidden.registerCustomHook('appWindow', function(bindingsAPI) {
+  var apiFunctions = bindingsAPI.apiFunctions;
+  apiFunctions.setCustomCallback('create', function(name, request, view_id) {

[Mihai Parparita -not on Chrome, 2012/05/29 06:14:42]

Nit: view_id should be called viewId per the JS style guide.

+    var view = null;
+    if (view_id)
+      view = GetView(view_id);
+    if (request.callback) {

[Mihai Parparita -not on Chrome, 2012/05/29 06:14:42]

Nit: This can become an early return at the start of the function (no point in
trying to get the view if no one wants it).

+      request.callback(view);
+      delete request.callback;
+    }
+  })
 });