Introduce PrefRegistrySyncable, simplifying PrefServiceSyncable.

chrome/browser/download/download_prefs.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_PREFS_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_PREFS_H_
 
 #include <set>
 
 #include "base/file_path.h"
 #include "base/prefs/public/pref_member.h"
 
-class PrefServiceSyncable;
+class PrefRegistrySyncable;
+class PrefService;
 class Profile;
 
 namespace content {
 class BrowserContext;
 class DownloadManager;
 }
 
 // Stores all download-related preferences.
 class DownloadPrefs {
  public:
   explicit DownloadPrefs(Profile* profile);
   ~DownloadPrefs();
 
-  static void RegisterUserPrefs(PrefServiceSyncable* prefs);
+  static void RegisterUserPrefs(PrefService* user_prefs,
+                                PrefRegistrySyncable* registry);
 
   // Returns the DownloadPrefs corresponding to the given DownloadManager
   // or BrowserContext.
   static DownloadPrefs* FromDownloadManager(
       content::DownloadManager* download_manager);
   static DownloadPrefs* FromBrowserContext(
       content::BrowserContext* browser_context);
 
   base::FilePath DownloadPath() const;
   int save_file_type() const { return *save_file_type_; }
@@ skipping 37 matching lines @@
                     const base::FilePath::StringType& b) const;
   };
   typedef std::set<base::FilePath::StringType,
                    AutoOpenCompareFunctor> AutoOpenSet;
   AutoOpenSet auto_open_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadPrefs);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_PREFS_H_