components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/bookmarks/bookmark_prompt_prefs.h

Index: chrome/browser/bookmarks/bookmark_prompt_prefs.h
diff --git a/chrome/browser/bookmarks/bookmark_prompt_prefs.h b/chrome/browser/bookmarks/bookmark_prompt_prefs.h
index 4e33e6cca0538e5fb6763cc0eede94bc1c505385..9bb0a70f3364247939b382975b4eba6551f84f4c 100644
--- a/chrome/browser/bookmarks/bookmark_prompt_prefs.h
+++ b/chrome/browser/bookmarks/bookmark_prompt_prefs.h
@@ -7,9 +7,12 @@
 
 #include "base/basictypes.h"
 
-class PrefRegistrySyncable;
 class PrefService;
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
 // Helper class for getting, changing bookmark prompt related preferences.
 class BookmarkPromptPrefs {
  public:
@@ -31,7 +34,7 @@ class BookmarkPromptPrefs {
   bool IsBookmarkPromptEnabled() const;
 
   // Registers user preferences used by bookmark prompt feature.
-  static void RegisterUserPrefs(PrefRegistrySyncable* registry);
+  static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* registry);
 
  private:
   PrefService* prefs_;  // Weak.