chromium/third_party/blink/web_tests/external/wpt/speculation-rules/prerender/resources/background-fetch.https.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/speculation-rules/prerender/resources/utils.js"></script>
<script src="/speculation-rules/prerender/resources/deferred-promise-utils.js"></script>
<script>

// The main test page (restriction-background-fetch.https.html) loads the
// initiator page, then the initiator page will prerender itself with the
// `prerendering` parameter.
const params = new URLSearchParams(location.search);
const isPrerendering = params.has('prerendering');

if (!isPrerendering) {
  const rule_extras = {'target_hint': getTargetHint()};
  loadInitiatorPage(rule_extras);
} else {
  async function loadPrerenderPage() {
    const prerenderEventCollector = new PrerenderEventCollector();
    const scope = `resources/`;
    const registration = await navigator.serviceWorker.getRegistration(scope);
    const fetch_promise = registration.backgroundFetch.fetch(
            'my-fetch', '/', {icons: [{src: '/'}]});
    prerenderEventCollector.start(fetch_promise, 'backgroundFetch.fetch');
  }
  loadPrerenderPage();
}

</script>