Move all typecasting code to individual screens.

chrome/browser/chromeos/login/screens/user_image_screen.h

Index: chrome/browser/chromeos/login/screens/user_image_screen.h
diff --git a/chrome/browser/chromeos/login/screens/user_image_screen.h b/chrome/browser/chromeos/login/screens/user_image_screen.h
index 5783e29c89ba906f25c61a1aaa3d94bfdc135bff..15820eba5a04689f5e44c610350be875a18301a2 100644
--- a/chrome/browser/chromeos/login/screens/user_image_screen.h
+++ b/chrome/browser/chromeos/login/screens/user_image_screen.h
@@ -8,6 +8,7 @@
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/chromeos/camera_presence_notifier.h"
+#include "chrome/browser/chromeos/login/screen_manager.h"

[ygorshenin1, 2014/09/03 13:30:22]

You dont' need inclusion of screen_manager.h here, as you already
forward-declared it. Move inclusion to the *.cc part.

 #include "chrome/browser/chromeos/login/screens/user_image_screen_actor.h"
 #include "chrome/browser/chromeos/login/screens/wizard_screen.h"
 #include "chrome/browser/chromeos/login/users/avatar/user_image_sync_observer.h"
@@ -28,6 +29,7 @@ class PolicyChangeRegistrar;
 namespace chromeos {
 
 class UserImageManager;
+class ScreenManager;
 
 class UserImageScreen: public WizardScreen,
                        public UserImageScreenActor::Delegate,
@@ -40,6 +42,8 @@ class UserImageScreen: public WizardScreen,
                   UserImageScreenActor* actor);
   virtual ~UserImageScreen();
 
+  static UserImageScreen* Get(ScreenManager* manager);
+
   // WizardScreen implementation:
   virtual void PrepareToShow() OVERRIDE;
   virtual void Show() OVERRIDE;