chromium/third_party/blink/web_tests/external/wpt/fs/resources/opaque-origin-sandbox.html

<!DOCTYPE html>
<script>
  'use strict'

  // Sends a message containing the result of navigator.storage.getDirectory()
  // to its creator.

  function post_message(data) {
    if (window.parent !== null) {
      window.parent.postMessage(data, { targetOrigin: '*' });
    }
    if (window.opener !== null) {
      window.opener.postMessage(data, { targetOrigin: '*' });
    }
  }

  try {
    navigator.storage.getDirectory()
      .then(() => {
        post_message('navigator.storage.getDirectory(): FULFILLED');
      }).catch(error => {
        post_message(`navigator.storage.getDirectory(): REJECTED: ${error.name}`);
      });
  } catch (error) {
    post_message(`navigator.storage.getDirectory(): EXCEPTION: ${error.name}`);
  }
</script>