components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/chromeos/login/oauth2_login_manager.h

Index: chrome/browser/chromeos/login/oauth2_login_manager.h
diff --git a/chrome/browser/chromeos/login/oauth2_login_manager.h b/chrome/browser/chromeos/login/oauth2_login_manager.h
index 8b006ffd7657c00a685f45ef41df8bae739ff5fb..ed2465402cecb9d17e9ca55a64826d7c7aec2104 100644
--- a/chrome/browser/chromeos/login/oauth2_login_manager.h
+++ b/chrome/browser/chromeos/login/oauth2_login_manager.h
@@ -16,10 +16,13 @@
 #include "net/url_request/url_request_context_getter.h"
 
 class GoogleServiceAuthError;
-class PrefRegistrySyncable;
 class Profile;
 class TokenService;
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
 namespace chromeos {
 
 // OAuth2 specialization of OAuthLoginManager.
@@ -31,7 +34,7 @@ class OAuth2LoginManager : public OAuthLoginManager,
   explicit OAuth2LoginManager(OAuthLoginManager::Delegate* delegate);
   virtual ~OAuth2LoginManager();
 
-  static void RegisterUserPrefs(PrefRegistrySyncable* registry);
+  static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // OAuthLoginManager overrides.
   virtual void RestoreSession(