Remove NOTIFICATION_SYSTEM_SETTING_CHANGED, switch CrosSettings to base::CallbackRegistry.

chrome/browser/chromeos/login/wallpaper_manager.h

Index: chrome/browser/chromeos/login/wallpaper_manager.h
diff --git a/chrome/browser/chromeos/login/wallpaper_manager.h b/chrome/browser/chromeos/login/wallpaper_manager.h
index 362dbab459c302a404ceed0faa47213d93e7076a..a56947cb74336f9dff9c5b65e7842dfc0bc22402 100644
--- a/chrome/browser/chromeos/login/wallpaper_manager.h
+++ b/chrome/browser/chromeos/login/wallpaper_manager.h
@@ -10,12 +10,14 @@
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted_memory.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/time/time.h"
 #include "chrome/browser/chromeos/login/user.h"
 #include "chrome/browser/chromeos/login/user_image.h"
 #include "chrome/browser/chromeos/login/user_image_loader.h"
+#include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "third_party/icu/source/i18n/unicode/timezone.h"
@@ -355,6 +357,9 @@ class WallpaperManager: public content::NotificationObserver {
 
   bool should_cache_wallpaper_;
 
+  scoped_ptr<CrosSettings::ObserverSubscription>
+      show_user_name_on_signin_subscription_;
+
   base::WeakPtrFactory<WallpaperManager> weak_factory_;
 
   content::NotificationRegistrar registrar_;