Move all typecasting code to individual screens.

chrome/browser/chromeos/login/users/avatar/user_image_sync_observer.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/chromeos/login/users/avatar/user_image_sync_observer.h"
 
 #include "base/bind.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 170 matching lines @@
 
 bool UserImageSyncObserver::GetSyncedImageIndex(int* index) {
   *index = user_manager::User::USER_IMAGE_INVALID;
   const base::DictionaryValue* dict = prefs_->GetDictionary(kUserImageInfo);
   return dict && dict->GetInteger(kImageIndex, index);
 }
 
 bool UserImageSyncObserver::CanUpdateLocalImageNow() {
   if (WizardController* wizard_controller =
           WizardController::default_controller()) {
-    UserImageScreen* screen = wizard_controller->GetUserImageScreen();
+    UserImageScreen* screen = UserImageScreen::Get(wizard_controller);
     if (wizard_controller->current_screen() == screen) {
       if (screen->user_selected_image())
         return false;
     }
   }
   return true;
 }
 
 }  // namespace chromeos