[Sync] Move //sync to //components/sync.

sync/api/metadata_change_list.h

-// Copyright 2015 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 SYNC_API_METADATA_CHANGE_LIST_H_
-#define SYNC_API_METADATA_CHANGE_LIST_H_
-
-#include <string>
-
-#include "sync/base/sync_export.h"
-
-namespace sync_pb {
-class DataTypeState;
-class EntityMetadata;
-}  // namespace sync_pb
-
-namespace syncer_v2 {
-
-// Interface used by the processor and service to communicate about metadata.
-// The purpose of the interface is to record changes to data type global and
-// per entity metadata for the purpose of propagating changes to the datatype
-// specific storage implementation.
-// The implementation of the interface is supposed to keep the record of all
-// updated / deleted metadata records and provide a mechanism to enumerate
-// them. If there are multiple UpdateMetadata / ClearMetadata calls made for the
-// same metadata record the last one is supposed to win.
-class SYNC_EXPORT MetadataChangeList {
- public:
-  MetadataChangeList() {}
-  virtual ~MetadataChangeList() {}
-
-  // Requests DataTypeState to be updated in the storage.
-  virtual void UpdateDataTypeState(
-      const sync_pb::DataTypeState& data_type_state) = 0;
-
-  // Requests DataTypeState to be cleared from the storage.
-  virtual void ClearDataTypeState() = 0;
-
-  // Requests metadata entry to be updated in the storage.
-  // Please note that the update might contain a deleted entry if
-  // metadata.is_deleted() is true (as opposed to clearing the entry from the
-  // storage completely by calling the Clear method).
-  virtual void UpdateMetadata(const std::string& client_tag,
-                              const sync_pb::EntityMetadata& metadata) = 0;
-
-  // Requests metadata entry to be cleared from the storage.
-  virtual void ClearMetadata(const std::string& client_tag) = 0;
-};
-
-}  // namespace syncer_v2
-
-#endif  // SYNC_API_METADATA_CHANGE_LIST_H_