components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/download/chrome_download_manager_delegate.h

Index: chrome/browser/download/chrome_download_manager_delegate.h
diff --git a/chrome/browser/download/chrome_download_manager_delegate.h b/chrome/browser/download/chrome_download_manager_delegate.h
index d6cedd4cbe4de048f29ac8bf33503eb58110336a..e97c9b1269023793d619664ec50cfcc1f3fcecb8 100644
--- a/chrome/browser/download/chrome_download_manager_delegate.h
+++ b/chrome/browser/download/chrome_download_manager_delegate.h
@@ -19,7 +19,6 @@
 #include "content/public/browser/notification_registrar.h"
 
 class DownloadPrefs;
-class PrefRegistrySyncable;
 class Profile;
 
 namespace content {
@@ -30,6 +29,10 @@ namespace extensions {
 class CrxInstaller;
 }
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
 #if defined(COMPILER_GCC)
 namespace BASE_HASH_NAMESPACE {
 template<>
@@ -50,7 +53,7 @@ class ChromeDownloadManagerDelegate
  public:
   explicit ChromeDownloadManagerDelegate(Profile* profile);
 
-  static void RegisterUserPrefs(PrefRegistrySyncable* registry);
+  static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // Should be called before the first call to ShouldCompleteDownload() to
   // disable SafeBrowsing checks for |item|.