[USS] implement CreateMetadataChangeList and GetClientTag

components/history/core/browser/history_backend.cc

 // Copyright (c) 2012 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.
 
 #include "components/history/core/browser/history_backend.h"
 
 #include <algorithm>
 #include <functional>
 #include <list>
 #include <map>
@@ skipping 201 matching lines @@
   // HistoryBackend is created on the UI thread by HistoryService, then the
   // HistoryBackend::Init() method is called on the DB thread. Create the
   // base::SupportsUserData on the DB thread since it is not thread-safe.
   supports_user_data_helper_.reset(new HistoryBackendHelper);
 
   if (!force_fail)
     InitImpl(history_database_params);
   delegate_->DBLoaded();
   if (base::FeatureList::IsEnabled(switches::kSyncUSSTypedURL)) {
     typed_url_sync_bridge_ = base::MakeUnique<TypedURLSyncBridge>(
-        this,
+        this, db_.get(),
         base::BindRepeating(
             &ModelTypeChangeProcessor::Create,
             // TODO(gangwu): use ReportUnrecoverableError before launch.
             base::BindRepeating(base::IgnoreResult(&DumpWithoutCrashing))));
   } else {
     typed_url_syncable_service_ =
         base::MakeUnique<TypedUrlSyncableService>(this);
   }
 
   memory_pressure_listener_.reset(new base::MemoryPressureListener(
@@ skipping 2402 matching lines @@
   // transaction is currently open.
   db_->CommitTransaction();
   db_->Vacuum();
   db_->BeginTransaction();
   db_->GetStartDate(&first_recorded_time_);
 
   return true;
 }
 
 }  // namespace history