Add layout tests for ServiceWorker's notificationclose event.

components/html_viewer/web_test_delegate_impl.cc

Index: components/html_viewer/web_test_delegate_impl.cc
diff --git a/components/html_viewer/web_test_delegate_impl.cc b/components/html_viewer/web_test_delegate_impl.cc
index 751b84267fd4613eefab1f2d5a560cdf8917097f..9d7e64887d36d0d2077843f3a56486fee6720c8b 100644
--- a/components/html_viewer/web_test_delegate_impl.cc
+++ b/components/html_viewer/web_test_delegate_impl.cc
@@ -194,6 +194,11 @@ void WebTestDelegateImpl::SimulateWebNotificationClick(
   NOTIMPLEMENTED();
 }
 
+void WebTestDelegateImpl::SimulateWebNotificationClose(
+    const std::string& title, bool by_user) {
+  NOTIMPLEMENTED();
+}
+
 void WebTestDelegateImpl::SetDeviceScaleFactor(float factor) {
   NOTIMPLEMENTED();
 }