[Sync] Create UserEventSyncBridge.

components/sync/user_events/user_event_sync_bridge.h

+// Copyright 2017 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_USER_EVENTS_USER_EVENT_SYNC_BRIDGE_H_
+#define COMPONENTS_SYNC_USER_EVENTS_USER_EVENT_SYNC_BRIDGE_H_
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "components/sync/model/model_type_store.h"
+#include "components/sync/model/model_type_sync_bridge.h"
+
+namespace syncer {
+
+class UserEventSyncBridge : public ModelTypeSyncBridge {
+ public:
+  UserEventSyncBridge(const ModelTypeStoreFactory& store_factory,
+                      const ChangeProcessorFactory& change_processor_factory);
+  ~UserEventSyncBridge() override;
+
+  // ModelTypeSyncBridge implementation.
+  std::unique_ptr<MetadataChangeList> CreateMetadataChangeList() override;
+  base::Optional<ModelError> MergeSyncData(
+      std::unique_ptr<MetadataChangeList> metadata_change_list,
+      EntityDataMap entity_data_map) override;
+  base::Optional<ModelError> ApplySyncChanges(
+      std::unique_ptr<MetadataChangeList> metadata_change_list,
+      EntityChangeList entity_changes) override;
+  void GetData(StorageKeyList storage_keys, DataCallback callback) override;
+  void GetAllData(DataCallback callback) override;
+  std::string GetClientTag(const EntityData& entity_data) override;
+  std::string GetStorageKey(const EntityData& entity_data) override;
+  void DisableSync() override;
+
+  void RecordUserEvent(std::unique_ptr<sync_pb::UserEventSpecifics> specifics);
+
+ private:
+  void OnStoreCreated(ModelTypeStore::Result result,
+                      std::unique_ptr<ModelTypeStore> store);
+  void OnReadAllMetadata(base::Optional<ModelError> error,
+                         std::unique_ptr<MetadataBatch> metadata_batch);
+  void OnCommit(ModelTypeStore::Result result);
+  void OnReadData(DataCallback callback,
+                  ModelTypeStore::Result result,
+                  std::unique_ptr<ModelTypeStore::RecordList> data_records,
+                  std::unique_ptr<ModelTypeStore::IdList> missing_id_list);
+  void OnReadAllData(DataCallback callback,
+                     ModelTypeStore::Result result,
+                     std::unique_ptr<ModelTypeStore::RecordList> data_records);
+  void OnReadAllDataToDelete(
+      ModelTypeStore::Result result,
+      std::unique_ptr<ModelTypeStore::RecordList> data_records);
+
+  // Persistent storage for in flight events. Should remain quite small, as we
+  // delete upon commit confirmation.
+  std::unique_ptr<ModelTypeStore> store_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserEventSyncBridge);
+};
+
+}  // namespace syncer
+
+#endif  // COMPONENTS_SYNC_USER_EVENTS_USER_EVENT_SYNC_BRIDGE_H_