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 9c7ee4cf07cc121606dca5a64293791577c42ac1..cbf7af5add84640df06e6fce247545246c42ce98 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"
@@ -285,9 +287,6 @@ class WallpaperManager: public content::NotificationObserver {
                  bool update_wallpaper,
                  const base::FilePath& wallpaper_path);
 
-  // True if wallpaper manager is not observering other objects.
-  bool no_observers_;
-
   // The number of loaded wallpapers.
   int loaded_wallpapers_;
 
@@ -317,6 +316,9 @@ 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_;