Implement new SyncAPI and convert Preferences to it.

chrome/browser/sync/glue/change_processor.h

 // Copyright (c) 2011 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_SYNC_GLUE_CHANGE_PROCESSOR_H_
 #define CHROME_BROWSER_SYNC_GLUE_CHANGE_PROCESSOR_H_
 #pragma once
 
 #include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
@@ skipping 42 matching lines @@
   virtual void CommitChangesFromSyncModel();
 
  protected:
   // These methods are invoked by Start() and Stop() to do
   // implementation-specific work.
   virtual void StartImpl(Profile* profile) = 0;
   virtual void StopImpl() = 0;
 
   bool running() { return running_; }
   UnrecoverableErrorHandler* error_handler();
-  sync_api::UserShare* share_handle();
+  virtual sync_api::UserShare* share_handle();
 
  private:
   bool running_;  // True if we have been told it is safe to process changes.
   UnrecoverableErrorHandler* error_handler_;  // Guaranteed to outlive us.
 
   // The sync model we are processing changes from. Non-NULL when |running_| is
   // true.
   sync_api::UserShare* share_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(ChangeProcessor);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_CHANGE_PROCESSOR_H_