worklets/resources/referrer-window.html

<!DOCTYPE html>
<html>
<head>
  <title>Worklet: Referrer</title>
  <script src="/common/get-host-info.sub.js"></script>
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
  <script src="worklet-test-utils.js"></script>
</head>
<body>
<script>
function createScriptURLForTopLevel(scriptOrigin) {
  if (scriptOrigin === 'same')
    return new URL('referrer-checker.py', location.href);
  if (scriptOrigin === 'remote') {
    return new URL(get_host_info().HTTPS_REMOTE_ORIGIN +
                   '/worklets/resources/referrer-checker.py');
  }
  assert_unreached('scriptOrigin should be \'same\' or \'remote\'');
}

function createScriptURLForDecendant(scriptOrigins) {
  if (scriptOrigins.topLevel === 'same' &&
      scriptOrigins.descendant === 'same') {
    return new URL('import-referrer-checker-worklet-script.sub.js',
                   location.href);
  }
  if (scriptOrigins.topLevel === 'same' &&
      scriptOrigins.descendant === 'remote') {
    return new URL(
        'import-remote-origin-referrer-checker-worklet-script.sub.js',
        location.href);
  }
  if (scriptOrigins.topLevel === 'remote' &&
      scriptOrigins.descendant === 'same') {
    url = new URL(
        get_host_info().HTTPS_REMOTE_ORIGIN +
        '/worklets/resources/' +
        'import-same-origin-referrer-checker-worklet-script-from-remote-origin.sub.js');
    return url;
  }
  if (scriptOrigins.topLevel === 'remote' &&
      scriptOrigins.descendant === 'remote') {
    return new URL(
        get_host_info().HTTPS_REMOTE_ORIGIN +
        '/worklets/resources/import-referrer-checker-worklet-script.sub.js');
  }
  assert_unreached('scriptOrigins have an invalid origin combination.');
}

function isDestinationCrossOrigin(fetchType, scriptOrigins) {
  if (fetchType === 'top-level')
    return scriptOrigins.topLevel === 'remote';

  // Compute a descendant's cross-origin-ness relative to the top-level script.
  if (fetchType === 'descendant')
    return scriptOrigins.descendant !== scriptOrigins.topLevel;
  assert_unreached('fetchType has an invalid value.');
}

function createExpectedReferrer(
    importerURL, fetchType, referrerPolicy, scriptOrigins) {
  if (referrerPolicy === 'no-referrer')
    return "";
  if (referrerPolicy === 'same-origin') {
    if (isDestinationCrossOrigin(fetchType, scriptOrigins))
      return "";
    // Delete query params to make it easier to match with an actual referrer in
    // the referrer-checker.py.
    const expectedReferrer = new URL(importerURL);
    for (var key of expectedReferrer.searchParams.keys())
      expectedReferrer.searchParams.delete(key);
    return expectedReferrer;
  }
  if (referrerPolicy === 'origin')
    return (new URL(importerURL)).origin + '/';
  assert_unreached('referrerPolicy has an invalid value.');
}

window.onmessage = e => {
  const workletType = e.data.workletType;
  const fetchType = e.data.fetchType;
  const referrerPolicy = e.data.referrerPolicy;
  const scriptOrigins = e.data.scriptOrigins;

  let scriptURL;
  let expectedReferrer;
  if (fetchType === 'top-level') {
    scriptURL = createScriptURLForTopLevel(scriptOrigins.topLevel);
    expectedReferrer = createExpectedReferrer(
        location.href, fetchType, referrerPolicy, scriptOrigins);
  } else if (fetchType === 'descendant') {
    scriptURL = createScriptURLForDecendant(scriptOrigins);
    expectedReferrer = createExpectedReferrer(
        scriptURL, fetchType, referrerPolicy, scriptOrigins);
  } else {
    assert_unreached('fetchType should be \'top-level\' or \'descendant\'');
  }

  const params = new URLSearchParams;
  params.append('requestor_origin', document.location.origin);
  params.append('referrer_policy', referrerPolicy);
  params.append('expected_referrer', expectedReferrer);

  get_worklet(workletType).addModule(scriptURL + '?' + params)
      .then(() => window.opener.postMessage('RESOLVED', '*'))
      .catch(e => window.opener.postMessage(e.message, '*'));
};

window.opener.postMessage('LOADED', '*');
</script>
</body>
</html>