Add PyAuto test for DeviceGuestModeEnabled policy

chrome/common/chrome_notification_types.h

 // 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.
 
 #ifndef CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_
 #define CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_
 #pragma once
 
 #include "content/public/browser/notification_types.h"
 
@@ skipping 855 matching lines @@
   // Sent when a chromium os user attempts to log in.  The source is
   // all and the details are AuthenticationNotificationDetails.
   NOTIFICATION_LOGIN_AUTHENTICATION,
 
   // Sent when webui lock screen is ready.
   NOTIFICATION_LOCK_WEBUI_READY,
 
   // Sent when webui login screen is ready and gaia iframe has loaded.
   NOTIFICATION_LOGIN_WEBUI_READY,
 
+  // Sent when the WebUI account picker is ready.
+  NOTIFICATION_ACCOUNT_PICKER_WEBUI_READY,
+
   // Sent when the user images on the WebUI login screen have all been loaded.
   NOTIFICATION_LOGIN_USER_IMAGES_LOADED,
 
   // Sent when proxy dialog is closed.
   NOTIFICATION_LOGIN_PROXY_CHANGED,
 
   // Sent when a network error message is displayed on the WebUI login screen.
   NOTIFICATION_LOGIN_NETWORK_ERROR_SHOWN,
 
   // Sent when the user list has changed due to a policy change.
@@ skipping 230 matching lines @@
   // Currently only Content and Chrome define and use notifications.
   // Custom notifications not belonging to Content and Chrome should start
   // from here.
   NOTIFICATION_CHROME_END,
 };
 
 }  // namespace chrome
 
 
 #endif  // CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_