chromium/chrome/test/data/privacy_budget/iframe_shared_worker.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Privacy Budget: Test page used as an iframe to add a client to a shared worker</title>
<script src="test_utils.js"></script>
<script language="javascript">
  const myWorker = new SharedWorker('two_clients_shared_worker.js');
  myWorker.port.onmessage = (e) => {
    sendValueToTest('Done');
  }
  myWorker.port.postMessage('Start');
</script>