Move all typecasting code to individual screens.

chrome/browser/chromeos/login/wizard_controller.h

Index: chrome/browser/chromeos/login/wizard_controller.h
diff --git a/chrome/browser/chromeos/login/wizard_controller.h b/chrome/browser/chromeos/login/wizard_controller.h
index ee03e9e786fba160c2e9ad570562c8bfe8359075..379571263e111eaf8df06901f05442aba8866038 100644
--- a/chrome/browser/chromeos/login/wizard_controller.h
+++ b/chrome/browser/chromeos/login/wizard_controller.h
@@ -19,6 +19,7 @@
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
+#include "chrome/browser/chromeos/login/screen_manager.h"
 #include "chrome/browser/chromeos/login/screens/screen_observer.h"
 
 class PrefRegistrySimple;
@@ -47,7 +48,7 @@ class UserImageScreen;
 
 // Class that manages control flow between wizard screens. Wizard controller
 // interacts with screen controllers to move the user between screens.
-class WizardController : public ScreenObserver {
+class WizardController : public ScreenObserver, public ScreenManager {
  public:
   // Observes screen changes.
   class Observer {
@@ -121,17 +122,6 @@ class WizardController : public ScreenObserver {
   // reworked at hackaton.
   void EnableUserImageScreenReturnToPreviousHack();
 
-  // Lazy initializers and getters for screens.
-  WizardScreen* GetScreen(const std::string& screen_name);
-  WizardScreen* CreateScreen(const std::string& screen_name);
-
-  // Typed getters for the screens.
-  NetworkScreen* GetNetworkScreen();
-  UpdateScreen* GetUpdateScreen();
-  UserImageScreen* GetUserImageScreen();
-  EnrollmentScreen* GetEnrollmentScreen();
-  AutoEnrollmentCheckScreen* GetAutoEnrollmentCheckScreen();
-  SupervisedUserCreationScreen* GetSupervisedUserCreationScreen();
 
   // Returns a pointer to the current screen or NULL if there's no such
   // screen.
@@ -140,6 +130,9 @@ class WizardController : public ScreenObserver {
   // Returns true if the current wizard instance has reached the login screen.
   bool login_screen_started() const { return login_screen_started_; }
 
+  // ScreenManager implementation.
+  virtual WizardScreen* CreateScreen(const std::string& screen_name) OVERRIDE;
+
   static const char kNetworkScreenName[];
   static const char kLoginScreenName[];
   static const char kUpdateScreenName[];