chromium/src/third_party/blink/web_tests/fast/dom/resources/raf-throttling-frame.html - manifest_repos/chromium_src - Git at Google

 <!DOCTYPE html>

 <!-- Counts the number of animation frames that have been served to this frame. -->
 <script>
 let rafCount = 0;
 function raf() {
   rafCount++;
   requestAnimationFrame(raf);
 };
 requestAnimationFrame(raf);

 addEventListener('message', (e) => {
   e.source.postMessage(rafCount, e.origin);
 });
 </script>
	<!DOCTYPE html>

	<!-- Counts the number of animation frames that have been served to this frame. -->
	<script>
	let rafCount = 0;
	function raf() {
	rafCount++;
	requestAnimationFrame(raf);
	};
	requestAnimationFrame(raf);

	addEventListener('message', (e) => {
	e.source.postMessage(rafCount, e.origin);
	});
	</script>