LayoutTests/http/tests/security/top-level-unique-origin2.https.html - WebKit - Git at Google

 <!DOCTYPE html>
 <body>
 <script>
     if (window.testRunner) {
         testRunner.waitUntilDone();
         testRunner.dumpAsText();
     }
     onmessage = (event) => {
         document.body.innerHTML = !event.data ? "PASS": "FAIL";
         if (window.testRunner)
             testRunner.notifyDone();
     };
     setTimeout(() => {
         document.body.innerHTML = "TIMEOUT";
         if (window.testRunner)
             testRunner.notifyDone();
     }, 10000);
 </script>
 <iframe src="data:text/html,<script>console.log('data URL frame loaded'); const blob = new Blob(['<'+ 'script>console.log(\'blob popup loaded\'); window.opener.postMessage(window.isSecureContext, \'*\'); console.log(\'blob popup message posted\'); <' + '/script>'], {type: 'text/html'}); const popup = window.open(URL.createObjectURL(blob)); onmessage = (event) => { parent.postMessage(event.data, '*'); popup.close(); }; console.log('blob popup opened'); </script>"></iframe>
 </body>
	<!DOCTYPE html>
	<body>
	<script>
	if (window.testRunner) {
	testRunner.waitUntilDone();
	testRunner.dumpAsText();
	}
	onmessage = (event) => {
	document.body.innerHTML = !event.data ? "PASS": "FAIL";
	if (window.testRunner)
	testRunner.notifyDone();
	};
	setTimeout(() => {
	document.body.innerHTML = "TIMEOUT";
	if (window.testRunner)
	testRunner.notifyDone();
	}, 10000);
	</script>
	<iframe src="data:text/html,<script>console.log('data URL frame loaded'); const blob = new Blob(['<'+ 'script>console.log(\'blob popup loaded\'); window.opener.postMessage(window.isSecureContext, \'\'); console.log(\'blob popup message posted\'); <' + '/script>'], {type: 'text/html'}); const popup = window.open(URL.createObjectURL(blob)); onmessage = (event) => { parent.postMessage(event.data, ''); popup.close(); }; console.log('blob popup opened'); </script>"></iframe>
	</body>