Move all typecasting code to individual screens.

chrome/browser/chromeos/login/screens/update_screen.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_CHROMEOS_LOGIN_SCREENS_UPDATE_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_UPDATE_SCREEN_H_
 
 #include <set>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/chromeos/login/screens/update_screen_actor.h"
 #include "chrome/browser/chromeos/login/screens/wizard_screen.h"
 #include "chromeos/dbus/update_engine_client.h"
 #include "chromeos/network/portal_detector/network_portal_detector.h"
 
 namespace chromeos {
 
 class ErrorScreen;
 class NetworkState;
+class ScreenManager;
 class ScreenObserver;
 
 // Controller for the update screen. It does not depend on the specific
 // implementation of the screen showing (Views of WebUI based), the dependency
 // is moved to the UpdateScreenActor instead.
 class UpdateScreen: public UpdateEngineClient::Observer,
                     public UpdateScreenActor::Delegate,
                     public WizardScreen,
                     public NetworkPortalDetector::Observer {
  public:
   UpdateScreen(ScreenObserver* screen_observer, UpdateScreenActor* actor);
   virtual ~UpdateScreen();
 
+  static UpdateScreen* Get(ScreenManager* manager);
+
   // Overridden from WizardScreen.
   virtual void PrepareToShow() OVERRIDE;
   virtual void Show() OVERRIDE;
   virtual void Hide() OVERRIDE;
   virtual std::string GetName() const OVERRIDE;
 
   // UpdateScreenActor::Delegate implementation:
   virtual void CancelUpdate() OVERRIDE;
   virtual void OnActorDestroyed(UpdateScreenActor* actor) OVERRIDE;
   virtual void OnConnectToNetworkRequested() OVERRIDE;
@@ skipping 114 matching lines @@
   bool is_first_portal_notification_;
 
   base::WeakPtrFactory<UpdateScreen> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UpdateScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_UPDATE_SCREEN_H_