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

chrome/common/extensions/api/app_window.idl

 // 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.
 
 // File-level comment to appease parser. Eventually this will not be necessary.
 
 [nodoc] namespace appWindow {
   dictionary CreateWindowOptions {
     // Width of the window.
     long? width;
 
     // Height of the window.
     long? height;
 
     long? left;
     long? top;
 
     // Window type: 'panel' or 'shell' (defaults to 'shell')
     DOMString? type;
 
     // Frame type: 'custom' or 'chrome' (defaults to 'chrome')
     DOMString? frame;
   };
 
   callback CreateWindowCallback = void (long view_id);
 
   interface Functions {
     static void create(DOMString url,
-                       CreateWindowOptions options,
-                       CreateWindowCallback callback);
+                       optional CreateWindowOptions options,
+                       optional CreateWindowCallback callback);
   };
 };