components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/notifications/desktop_notification_service.h

Index: chrome/browser/notifications/desktop_notification_service.h
diff --git a/chrome/browser/notifications/desktop_notification_service.h b/chrome/browser/notifications/desktop_notification_service.h
index 39d55d23497524f6fc647d5364c5282e0fc31d72..51aef63432e4131142b0ea66b1f985316d97c701 100644
--- a/chrome/browser/notifications/desktop_notification_service.h
+++ b/chrome/browser/notifications/desktop_notification_service.h
@@ -27,7 +27,6 @@ class ContentSettingsPattern;
 class Notification;
 class NotificationDelegate;
 class NotificationUIManager;
-class PrefRegistrySyncable;
 class Profile;
 
 namespace content {
@@ -39,6 +38,10 @@ namespace gfx {
 class Image;
 }
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
 // The DesktopNotificationService is an object, owned by the Profile,
 // which provides the creation of desktop "toasts" to web pages and workers.
 class DesktopNotificationService : public ProfileKeyedService {
@@ -49,7 +52,7 @@ class DesktopNotificationService : public ProfileKeyedService {
   };
 
   // Register profile-specific prefs of notifications.
-  static void RegisterUserPrefs(PrefRegistrySyncable* prefs);
+  static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* prefs);
 
   DesktopNotificationService(Profile* profile,
                              NotificationUIManager* ui_manager);