Use callback_forward.h instead of callback.h where possible.

chrome/browser/sync/glue/history_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_HISTORY_MODEL_WORKER_H_
 #define CHROME_BROWSER_SYNC_GLUE_HISTORY_MODEL_WORKER_H_
 #pragma once
 
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/util/unrecoverable_error_info.h"
 
 #include "base/basictypes.h"
-#include "base/callback.h"
+#include "base/callback_forward.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "content/browser/cancelable_request.h"
 
 class HistoryService;
 
 namespace browser_sync {
 
 // A ModelSafeWorker for history models that accepts requests
 // from the syncapi that need to be fulfilled on the history thread.
@@ skipping 11 matching lines @@
   scoped_refptr<HistoryService> history_service_;
   // Helper object to make sure we don't leave tasks running on the history
   // thread.
   CancelableRequestConsumerT<int, 0> cancelable_consumer_;
   DISALLOW_COPY_AND_ASSIGN(HistoryModelWorker);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_HISTORY_MODEL_WORKER_H_