speculation-rules/prerender/activation-start.https.html

<!DOCTYPE html>
<title>PerformanceNavigationTiming's activationStart in prerendered page</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script>
<script src="/common/dispatcher/dispatcher.js"></script>
<script src="/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js"></script>
<script src="../resources/utils.js"></script>
<script src="resources/utils.js"></script>

<body>
<script>
setup(() => assertSpeculationRulesIsSupported());

promise_test(async t => {
  const ACTIVATION_DELAY = 10;

  const rcHelper = new PrerenderingRemoteContextHelper();
  const referrerRC = await rcHelper.addWindow(undefined, { features: 'noopener' });
  const prerenderedRC = await referrerRC.addPrerender();
  const iframeRC = await prerenderedRC.addIframe();

  assert_equals(
    await getActivationStart(prerenderedRC),
    0,
    'activationStart must be 0 while prerendering'
  );

  assert_equals(
    await getActivationStart(iframeRC),
    0,
    'activationStart must be 0 while prerendering the iframe'
  );

  // Wait ACTIVATION_DELAY ms before activation.
  await new Promise(resolve => t.step_timeout(resolve, ACTIVATION_DELAY));

  await referrerRC.navigateExpectingPrerenderingActivation(prerenderedRC);

  assert_greater_than_equal(
    await getActivationStart(prerenderedRC),
    ACTIVATION_DELAY,
    'activationStart after activation must be greater than or equal to ' +
    'ACTIVATION_DELAY'
  );

  assert_greater_than_equal(
    await getActivationStart(iframeRC),
    ACTIVATION_DELAY,
    'activationStart after activation must be greater than or equal to ' +
    'ACTIVATION_DELAY in the iframe'
  );
});

// A utility to both extract activationStart from the prerendered
// RemoteContextWrapper, and also check that it shows up in toJSON().
async function getActivationStart(prerenderedRC) {
  const [activationStart, activationStartInToJSON] = await prerenderedRC.executeScript(() => {
    const entry = performance.getEntriesByType("navigation")[0];
    return [entry.activationStart, entry.toJSON().activationStart];
  });

  assert_equals(
    activationStart,
    activationStartInToJSON,
    "activationStart value must be available in the result of toJSON()"
  );

  return activationStart;
}
</script>