[USS] Implement ApplySyncChanges and OnURLVisited/Modified/Deleted.

components/history/core/browser/typed_url_sync_metadata_database.h

Index: components/history/core/browser/typed_url_sync_metadata_database.h
diff --git a/components/history/core/browser/typed_url_sync_metadata_database.h b/components/history/core/browser/typed_url_sync_metadata_database.h
index 6967f48642d88e61e4162faca3e1b587b91dc9f2..a48548cfd8f6f45e848506dd0dfc2eaa051eefcd 100644
--- a/components/history/core/browser/typed_url_sync_metadata_database.h
+++ b/components/history/core/browser/typed_url_sync_metadata_database.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_HISTORY_CORE_BROWSER_TYPED_URL_SYNC_METADATA_DATABASE_H_
 
 #include "base/macros.h"
+#include "components/history/core/browser/url_row.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/model/metadata_batch.h"
 #include "components/sync/model/sync_metadata_store.h"
@@ -43,6 +44,8 @@ class TypedURLSyncMetadataDatabase : public syncer::SyncMetadataStore {
       const sync_pb::ModelTypeState& model_type_state) override;
   bool ClearModelTypeState(syncer::ModelType model_type) override;
 
+  static URLID StorageKeyToURLID(const std::string& storage_key);
+
  protected:
   // Returns the database for the functions in this interface.
   virtual sql::Connection& GetDB() = 0;