Add PyAuto test for DeviceGuestModeEnabled policy

chrome/browser/automation/automation_provider_observers.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_BROWSER_AUTOMATION_AUTOMATION_PROVIDER_OBSERVERS_H_
 #define CHROME_BROWSER_AUTOMATION_AUTOMATION_PROVIDER_OBSERVERS_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 125 matching lines @@
   virtual ~NetworkManagerInitObserver();
   virtual bool Init();
   virtual void OnNetworkManagerChanged(chromeos::NetworkLibrary* obj);
 
  private:
   base::WeakPtr<AutomationProvider> automation_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkManagerInitObserver);
 };
 
-// Observes when webui login becomes ready on chromeos.
+// Observes when the ChromeOS login WebUI becomes ready (by showing the login
+// form, account picker, a network error or the OOBE wizard, depending on Chrome
+// flags and state).
 class LoginWebuiReadyObserver : public content::NotificationObserver {
  public:
   explicit LoginWebuiReadyObserver(AutomationProvider* automation);
-  virtual ~LoginWebuiReadyObserver();
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details);
 
  private:
   content::NotificationRegistrar registrar_;
   base::WeakPtr<AutomationProvider> automation_;
 
   DISALLOW_COPY_AND_ASSIGN(LoginWebuiReadyObserver);
 };
@@ skipping 1649 matching lines @@
  private:
   base::WeakPtr<AutomationProvider> automation_;
   scoped_ptr<IPC::Message> reply_message_;
   std::string extension_id_;
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPopupObserver);
 };
 
 #endif  // CHROME_BROWSER_AUTOMATION_AUTOMATION_PROVIDER_OBSERVERS_H_