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

sync/api/model_type_service.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_MODEL_TYPE_SERVICE_H_
-#define SYNC_API_MODEL_TYPE_SERVICE_H_
-
-#include <memory>
-#include <string>
-#include <vector>
-
-#include "base/callback.h"
-#include "sync/api/conflict_resolution.h"
-#include "sync/api/entity_change.h"
-#include "sync/api/entity_data.h"
-#include "sync/api/model_type_change_processor.h"
-#include "sync/api/sync_error.h"
-#include "sync/base/sync_export.h"
-#include "sync/internal_api/public/activation_context.h"
-
-namespace syncer {
-class DataTypeErrorHandler;
-}  // namespace syncer
-
-namespace syncer_v2 {
-
-class DataBatch;
-class MetadataChangeList;
-
-// Interface implemented by model types to receive updates from sync via the
-// SharedModelTypeProcessor. Provides a way for sync to update the data and
-// metadata for entities, as well as the model type state.
-class SYNC_EXPORT ModelTypeService {
- public:
-  typedef base::Callback<void(syncer::SyncError, std::unique_ptr<DataBatch>)>
-      DataCallback;
-  typedef std::vector<std::string> ClientTagList;
-  typedef base::Callback<std::unique_ptr<ModelTypeChangeProcessor>(
-      syncer::ModelType type,
-      ModelTypeService* service)>
-      ChangeProcessorFactory;
-
-  ModelTypeService(const ChangeProcessorFactory& change_processor_factory,
-                   syncer::ModelType type);
-
-  virtual ~ModelTypeService();
-
-  // Creates an object used to communicate changes in the sync metadata to the
-  // model type store.
-  virtual std::unique_ptr<MetadataChangeList> CreateMetadataChangeList() = 0;
-
-  // Perform the initial merge between local and sync data. This should only be
-  // called when a data type is first enabled to start syncing, and there is no
-  // sync metadata. Best effort should be made to match local and sync data. The
-  // keys in the |entity_data_map| will have been created via GetClientTag(...),
-  // and if a local and sync data should match/merge but disagree on tags, the
-  // service should use the sync data's tag. Any local pieces of data that are
-  // not present in sync should immediately be Put(...) to the processor before
-  // returning. The same MetadataChangeList that was passed into this function
-  // can be passed to Put(...) calls. Delete(...) can also be called but should
-  // not be needed for most model types. Durable storage writes, if not able to
-  // combine all change atomically, should save the metadata after the data
-  // changes, so that this merge will be re-driven by sync if is not completely
-  // saved during the current run.
-  virtual syncer::SyncError MergeSyncData(
-      std::unique_ptr<MetadataChangeList> metadata_change_list,
-      EntityDataMap entity_data_map) = 0;
-
-  // Apply changes from the sync server locally.
-  // Please note that |entity_changes| might have fewer entries than
-  // |metadata_change_list| in case when some of the data changes are filtered
-  // out, or even be empty in case when a commit confirmation is processed and
-  // only the metadata needs to persisted.
-  virtual syncer::SyncError ApplySyncChanges(
-      std::unique_ptr<MetadataChangeList> metadata_change_list,
-      EntityChangeList entity_changes) = 0;
-
-  // Asynchronously retrieve the corresponding sync data for |client_tags|.
-  virtual void GetData(ClientTagList client_tags, DataCallback callback) = 0;
-
-  // Asynchronously retrieve all of the local sync data.
-  virtual void GetAllData(DataCallback callback) = 0;
-
-  // Get or generate a client tag for |entity_data|.
-  virtual std::string GetClientTag(const EntityData& entity_data) = 0;
-
-  // Overridable notification for when the processor is set. This is typically
-  // when the service should start loading metadata and then subsequently giving
-  // it to the processor.
-  virtual void OnChangeProcessorSet() = 0;
-
-  // Resolve a conflict between the client and server versions of data. They are
-  // guaranteed not to match (both be deleted or have identical specifics). A
-  // default implementation chooses the server data unless it is a deletion.
-  virtual ConflictResolution ResolveConflict(
-      const EntityData& local_data,
-      const EntityData& remote_data) const;
-
-  // Called by the DataTypeController to gather additional information needed
-  // before the processor can be connected to a sync worker. Once the
-  // metadata has been loaded, the info is collected and given to |callback|.
-  void OnSyncStarting(syncer::DataTypeErrorHandler* error_handler,
-                      const ModelTypeChangeProcessor::StartCallback& callback);
-
-  // Indicates that we no longer want to do any sync-related things for this
-  // data type. Severs all ties to the sync thread, deletes all local sync
-  // metadata, and then destroys the change processor.
-  // TODO(crbug.com/584365): This needs to be called from DataTypeController.
-  void DisableSync();
-
- protected:
-  void CreateChangeProcessor();
-
-  ModelTypeChangeProcessor* change_processor() const;
-
-  void clear_change_processor();
-
- private:
-  std::unique_ptr<ModelTypeChangeProcessor> change_processor_;
-
-  ChangeProcessorFactory change_processor_factory_;
-
-  const syncer::ModelType type_;
-};
-
-}  // namespace syncer_v2
-
-#endif  // SYNC_API_MODEL_TYPE_SERVICE_H_