[Sync] Move ChangeProcessor to model/.

components/sync/driver/change_processor.cc

-// Copyright 2014 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/driver/change_processor.h"
-
-#include <utility>
-
-namespace syncer {
-
-ChangeProcessor::ChangeProcessor(
-    std::unique_ptr<DataTypeErrorHandler> error_handler)
-    : error_handler_(std::move(error_handler)), share_handle_(nullptr) {}
-
-ChangeProcessor::~ChangeProcessor() {}
-
-void ChangeProcessor::Start(UserShare* share_handle) {
-  DCHECK(!share_handle_);
-  share_handle_ = share_handle;
-  StartImpl();
-}
-
-// Not implemented by default.
-void ChangeProcessor::CommitChangesFromSyncModel() {}
-
-DataTypeErrorHandler* ChangeProcessor::error_handler() const {
-  return error_handler_.get();
-}
-
-UserShare* ChangeProcessor::share_handle() const {
-  return share_handle_;
-}
-
-}  // namespace syncer