chromium/src/third_party/blink/web_tests/http/tests/dom/resources/unthrottling-oopif-dirties-subframe-frame.html - manifest_repos/chromium_src - Git at Google

 <!DOCTYPE html>
 <iframe srcdoc="<div>Hello, world!</div>"></iframe>
 <script>
 self.addEventListener("message", evt => {
   let timeout_id = setTimeout(() => {
     timeout_id = 0;
     evt.source.postMessage("TIMEOUT", "*");
   }, 1000);
   requestAnimationFrame(() => {
     if (timeout_id)
       clearTimeout(timeout_id);
     evt.source.postMessage("SUCCESS", "*");
   });
 });
 </script>
	<!DOCTYPE html>
	<iframe srcdoc="<div>Hello, world!</div>"></iframe>
	<script>
	self.addEventListener("message", evt => {
	let timeout_id = setTimeout(() => {
	timeout_id = 0;
	evt.source.postMessage("TIMEOUT", "*");
	}, 1000);
	requestAnimationFrame(() => {
	if (timeout_id)
	clearTimeout(timeout_id);
	evt.source.postMessage("SUCCESS", "*");
	});
	});
	</script>