components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/translate/translate_prefs.h

Index: chrome/browser/translate/translate_prefs.h
diff --git a/chrome/browser/translate/translate_prefs.h b/chrome/browser/translate/translate_prefs.h
index 3c30ee4b751283f1204c669b8db84709a1e225c4..214fe6d75eaec9321f60d04f4a22763d757d26b0 100644
--- a/chrome/browser/translate/translate_prefs.h
+++ b/chrome/browser/translate/translate_prefs.h
@@ -9,7 +9,6 @@
 
 #include "googleurl/src/gurl.h"
 
-class PrefRegistrySyncable;
 class PrefService;
 
 namespace base {
@@ -17,6 +16,10 @@ class DictionaryValue;
 class ListValue;
 }
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
 class TranslatePrefs {
  public:
   static const char kPrefTranslateLanguageBlacklist[];
@@ -71,7 +74,7 @@ class TranslatePrefs {
       const std::string& original_language, const GURL& url);
   static bool ShouldAutoTranslate(PrefService* user_prefs,
       const std::string& original_language, std::string* target_language);
-  static void RegisterUserPrefs(PrefRegistrySyncable* registry);
+  static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* registry);
   static void MigrateUserPrefs(PrefService* user_prefs);
 
  private: