[Sync] Make ModelSafeWorker a true interface

chrome/browser/sync/glue/browser_thread_model_worker.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_BROWSER_THREAD_MODEL_WORKER_H_
 #define CHROME_BROWSER_SYNC_GLUE_BROWSER_THREAD_MODEL_WORKER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/util/unrecoverable_error_info.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace base {
 class WaitableEvent;
 }
 
 namespace browser_sync {
 
 // A ModelSafeWorker for models that accept requests from the syncapi that need
 // to be fulfilled on a browser thread, for example autofill on the DB thread.
 // TODO(sync): Try to generalize other ModelWorkers (e.g. history, etc).
-class BrowserThreadModelWorker : public browser_sync::ModelSafeWorker {
+class BrowserThreadModelWorker : public ModelSafeWorker {
  public:
   BrowserThreadModelWorker(content::BrowserThread::ID thread,
                            ModelSafeGroup group);
   virtual ~BrowserThreadModelWorker();
 
   // ModelSafeWorker implementation. Called on the sync thread.
   virtual UnrecoverableErrorInfo DoWorkAndWaitUntilDone(
       const WorkCallback& work) OVERRIDE;
   virtual ModelSafeGroup GetModelSafeGroup() OVERRIDE;
 
@@ skipping 36 matching lines @@
  protected:
   virtual void CallDoWorkAndSignalTask(
       const WorkCallback& work,
       base::WaitableEvent* done,
       UnrecoverableErrorInfo* error_info) OVERRIDE;
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_BROWSER_THREAD_MODEL_WORKER_H_