third_party/web_platform_tests/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/close_beforeunload-1.html - cobalt - Git at Google

 <!doctype html>
 <script>
 onload = function() {opener.postMessage("loaded", "*")};
 onbeforeunload = function() {
   opener.callback();
 }
 </script>
	<!doctype html>
	<script>
	onload = function() {opener.postMessage("loaded", "*")};
	onbeforeunload = function() {
	opener.callback();
	}
	</script>