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

sync/engine/update_handler.h

-// 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.
-
-#ifndef SYNC_ENGINE_UPDATE_HANDLER_H_
-#define SYNC_ENGINE_UPDATE_HANDLER_H_
-
-#include <vector>
-
-#include "sync/base/sync_export.h"
-#include "sync/internal_api/public/util/syncer_error.h"
-
-namespace sync_pb {
-class DataTypeContext;
-class DataTypeProgressMarker;
-class SyncEntity;
-}
-
-typedef std::vector<const sync_pb::SyncEntity*> SyncEntityList;
-
-namespace syncer {
-
-namespace sessions {
-class StatusController;
-}
-
-class ModelSafeWorker;
-
-// This class represents an entity that can request, receive, and apply updates
-// from the sync server.
-class SYNC_EXPORT UpdateHandler {
- public:
-  UpdateHandler();
-  virtual ~UpdateHandler() = 0;
-
-  // Returns true if initial sync was performed for this type.
-  virtual bool IsInitialSyncEnded() const = 0;
-
-  // Fills the given parameter with the stored progress marker for this type.
-  virtual void GetDownloadProgress(
-      sync_pb::DataTypeProgressMarker* progress_marker) const = 0;
-
-  // Fills |context| with the per-client datatype context, if one exists. Clears
-  // |context| otherwise.
-  virtual void GetDataTypeContext(sync_pb::DataTypeContext* context) const = 0;
-
-  // Processes the contents of a GetUpdates response message.
-  //
-  // Should be invoked with the progress marker and set of SyncEntities from a
-  // single GetUpdates response message.  The progress marker's type must match
-  // this update handler's type, and the set of SyncEntities must include all
-  // entities of this type found in the response message.
-  //
-  // In this context, "applicable_updates" means the set of updates belonging to
-  // this type.
-  //
-  // Returns SYNCER_OK if the all data was processed successfully, a syncer
-  // error otherwise.
-  virtual SyncerError ProcessGetUpdatesResponse(
-      const sync_pb::DataTypeProgressMarker& progress_marker,
-      const sync_pb::DataTypeContext& mutated_context,
-      const SyncEntityList& applicable_updates,
-      sessions::StatusController* status) = 0;
-
-  // Called at the end of a non-configure GetUpdates loop to apply any unapplied
-  // updates.
-  virtual void ApplyUpdates(sessions::StatusController* status) = 0;
-
-  // Called at the end of a configure GetUpdates loop to perform any required
-  // post-initial-download update application.
-  virtual void PassiveApplyUpdates(sessions::StatusController* status) = 0;
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_ENGINE_UPDATE_HANDLER_H_