[sync] Set up notification-free infra for triggering local sync refresh

components/sync_driver/fake_sync_service.cc

Index: components/sync_driver/fake_sync_service.cc
diff --git a/components/sync_driver/fake_sync_service.cc b/components/sync_driver/fake_sync_service.cc
index f8d37194fb9cea337242dcbea19135b4a29f4cf3..38b05ba5c2359e3372d3c6ab3f60a7d628a5eb0b 100644
--- a/components/sync_driver/fake_sync_service.cc
+++ b/components/sync_driver/fake_sync_service.cc
@@ -30,6 +30,8 @@ bool FakeSyncService::IsSyncActive() const {
   return false;
 }
 
+void FakeSyncService::TriggerRefresh(const syncer::ModelTypeSet& types) {}
+
 syncer::ModelTypeSet FakeSyncService::GetActiveDataTypes() const {
   return syncer::ModelTypeSet();
 }