[Sync] Move network-related code from core/ to engine/net/.

components/sync/core/network_time_update_callback.h

-// Copyright 2013 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 COMPONENTS_SYNC_CORE_NETWORK_TIME_UPDATE_CALLBACK_H_
-#define COMPONENTS_SYNC_CORE_NETWORK_TIME_UPDATE_CALLBACK_H_
-
-#include "base/callback.h"
-#include "base/time/time.h"
-
-namespace syncer {
-
-// TODO(pvalenzuela): Avoid duplication of this typedef by defining it in a
-// common location. This is duplicated here because its original definition in
-// NetworkTimeTracker cannot be depended on.
-//
-// Callback for updating the network time.
-// Params:
-// const base::Time& network_time - the new network time.
-// const base::TimeDelta& resolution - how precise the reading is.
-// const base::TimeDelta& latency - the http request's latency.
-typedef base::Callback<
-    void(const base::Time&, const base::TimeDelta&, const base::TimeDelta&)>
-    NetworkTimeUpdateCallback;
-
-}  // namespace syncer
-
-#endif  // COMPONENTS_SYNC_CORE_NETWORK_TIME_UPDATE_CALLBACK_H_