[BackgroundSync] Add browser side support for SyncRegistration.done

content/browser/background_sync/background_sync_registration_handle.cc

Index: content/browser/background_sync/background_sync_registration_handle.cc
diff --git a/content/browser/background_sync/background_sync_registration_handle.cc b/content/browser/background_sync/background_sync_registration_handle.cc
index ff89cca60f8b55082d2c79657c22e971248f40d8..4e5e8e809fea97970bf9fa821208d5ce60cfc572 100644
--- a/content/browser/background_sync/background_sync_registration_handle.cc
+++ b/content/browser/background_sync/background_sync_registration_handle.cc
@@ -26,6 +26,15 @@ void BackgroundSyncRegistrationHandle::Unregister(
       sw_registration_id, options()->periodicity, handle_id_, callback);
 }
 
+void BackgroundSyncRegistrationHandle::NotifyWhenDone(
+    const StatusAndStateCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(IsValid());
+  DCHECK(background_sync_manager_);
+
+  background_sync_manager_->NotifyWhenDone(handle_id_, callback);
+}
+
 bool BackgroundSyncRegistrationHandle::IsValid() const {
   return registration_ != nullptr;
 }