Move all typecasting code to individual screens.

chrome/browser/chromeos/login/screens/network_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_NETWORK_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_NETWORK_SCREEN_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/chromeos/login/screens/network_screen_actor.h"
 #include "chrome/browser/chromeos/login/screens/wizard_screen.h"
 #include "chromeos/network/network_state_handler_observer.h"
 
 namespace chromeos {
 
+class ScreenManager;
+
 namespace login {
 class NetworkStateHelper;
 }  // namespace login
 
 class NetworkScreen : public WizardScreen,
                       public NetworkStateHandlerObserver,
                       public NetworkScreenActor::Delegate {
  public:
   NetworkScreen(ScreenObserver* screen_observer, NetworkScreenActor* actor);
   virtual ~NetworkScreen();
 
+  static NetworkScreen* Get(ScreenManager* manager);
+
   // WizardScreen implementation:
   virtual void PrepareToShow() OVERRIDE;
   virtual void Show() OVERRIDE;
   virtual void Hide() OVERRIDE;
   virtual std::string GetName() const OVERRIDE;
 
   // NetworkStateHandlerObserver implementation:
   virtual void NetworkConnectionStateChanged(
       const NetworkState* network) OVERRIDE;
   virtual void DefaultNetworkChanged(const NetworkState* network) OVERRIDE;
@@ skipping 54 matching lines @@
 
   NetworkScreenActor* actor_;
   scoped_ptr<login::NetworkStateHelper> network_state_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_NETWORK_SCREEN_H_