Cleanup: Remove unneeded forward declarations in chrome/browser/sync.

chrome/browser/sync/engine/clear_data_command.h

-// Copyright (c) 2006-2010 The Chromium Authors. All rights reserved.
+// 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_ENGINE_CLEAR_DATA_COMMAND_H_
 #define CHROME_BROWSER_SYNC_ENGINE_CLEAR_DATA_COMMAND_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/engine/syncer_command.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 
-namespace sync_pb {
-class EntitySpecifics;
-}
-
 namespace browser_sync {
 
 // Clears server data associated with this user's account
 class ClearDataCommand : public SyncerCommand {
  public:
   ClearDataCommand();
   virtual ~ClearDataCommand();
 
   // SyncerCommand implementation.
   virtual void ExecuteImpl(sessions::SyncSession* session);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ClearDataCommand);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_CLEAR_DATA_COMMAND_H_
-