[Sync] Removing duplicated includes between cc and h files.

components/sync/engine/model_safe_worker.cc

 // 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.
 
 #include "components/sync/engine/model_safe_worker.h"
 
-#include <memory>
-
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/values.h"
 
 namespace syncer {
 
 std::unique_ptr<base::DictionaryValue> ModelSafeRoutingInfoToValue(
     const ModelSafeRoutingInfo& routing_info) {
   std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue());
@@ skipping 172 matching lines @@
       return;
     DCHECK(working_task_runner_->BelongsToCurrentThread());
   }
 
   DCHECK(stopped_);
   base::MessageLoop::current()->RemoveDestructionObserver(this);
   unregister_done_callback.Run(GetModelSafeGroup());
 }
 
 }  // namespace syncer