[sync] skeleton implementation of TypedURLSyncBridge

components/history/core/browser/typed_url_sync_bridge.h

Index: components/history/core/browser/typed_url_sync_bridge.h
diff --git a/components/history/core/browser/typed_url_sync_bridge.h b/components/history/core/browser/typed_url_sync_bridge.h
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+++ b/components/history/core/browser/typed_url_sync_bridge.h
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+// 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_HISTORY_CORE_BROWSER_TYPED_URL_SYNC_BRIDGE_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_TYPED_URL_SYNC_BRIDGE_H_
+
+#include "components/history/core/browser/history_backend_observer.h"
+#include "components/sync/model/metadata_change_list.h"
+#include "components/sync/model/model_type_sync_bridge.h"
+#include "components/sync/model/sync_error.h"
+
+namespace history {
+
+class TypedURLSyncBridge : public syncer::ModelTypeSyncBridge,
+                           public history::HistoryBackendObserver {
+ public:
+  TypedURLSyncBridge(HistoryBackend* history_backend,
+                     const ChangeProcessorFactory& change_processor_factory);
+  ~TypedURLSyncBridge() override;
+
+  // syncer::ModelTypeService implementation.
+  std::unique_ptr<syncer::MetadataChangeList> CreateMetadataChangeList()
+      override;
+  base::Optional<syncer::ModelError> MergeSyncData(
+      std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
+      syncer::EntityDataMap entity_data_map) override;
+  base::Optional<syncer::ModelError> ApplySyncChanges(
+      std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
+      syncer::EntityChangeList entity_changes) override;
+  void GetData(StorageKeyList storage_keys, DataCallback callback) override;
+  void GetAllData(DataCallback callback) override;
+  std::string GetClientTag(const syncer::EntityData& entity_data) override;
+  std::string GetStorageKey(const syncer::EntityData& entity_data) override;
+
+  // history::HistoryBackendObserver:
+  void OnURLVisited(history::HistoryBackend* history_backend,
+                    ui::PageTransition transition,
+                    const history::URLRow& row,
+                    const history::RedirectList& redirects,
+                    base::Time visit_time) override;
+  void OnURLsModified(history::HistoryBackend* history_backend,
+                      const history::URLRows& changed_urls) override;
+  void OnURLsDeleted(history::HistoryBackend* history_backend,
+                     bool all_history,
+                     bool expired,
+                     const history::URLRows& deleted_rows,
+                     const std::set<GURL>& favicon_urls) override;
+
+ private:
+  // The backend we're syncing local changes from and sync changes to.
+  HistoryBackend* const history_backend_;
+
+  // Since HistoryBackend use SequencedTaskRunner, so should use SequenceChecker
+  // here.
+  base::SequenceChecker sequence_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(TypedURLSyncBridge);
+};
+
+}  // namespace history
+
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_TYPED_URL_SYNC_BRIDGE_H_