chromium/third_party/blink/web_tests/external/wpt/speculation-rules/prerender/workers-in-cross-origin-iframe.html

<!DOCTYPE html>
<title>Construction of Web Workers in cross-origin iframe is deferred</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/get-host-info.sub.js"></script>
<script src="/common/utils.js"></script>
<script src="/common/dispatcher/dispatcher.js"></script>
<script src="../resources/utils.js"></script>
<script src="resources/utils.js"></script>

<!-- This is a regression test for https://crbug.com/1424250 -->
<body>
<script>
setup(() => assertSpeculationRulesIsSupported());

promise_test(async t => {
  const uid = token();
  const bc = new PrerenderChannel('test-channel', uid);
  const gotMessage = new Promise(resolve => {
    bc.addEventListener('message', e => {
      resolve(e.data);
    }, {once: true});
  });

  // This cross-origin iframe starts a dedicated worker and sends a message to
  // this document once loading the worker is completed.
  const crossOriginUrl =
      new URL(`resources/workers-in-cross-origin-iframe.html?uid=${uid}`,
              get_host_info()['HTTPS_REMOTE_ORIGIN'] +
                  window.location.pathname);

  // Start prerendering. Loading the cross-origin iframe in a prerendered page
  // will be deferred until prerender activation.
  const {exec, activate} = await create_prerendered_page(t);
  await exec(crossOriginUrl => {
    const iframe = document.createElement('iframe');
    iframe.src = crossOriginUrl;
    document.body.appendChild(iframe);
  }, [crossOriginUrl.href]);

  // Activate. This resumes loading the cross-origin iframe.
  await activate();

  // Wait for the completion of the worker creation.
  assert_equals(await gotMessage, 'Success');
}, "Dedicated workers in cross-origin iframe should be loaded after " +
   "activation");
</script>