<!--
  Any copyright is dedicated to the Public Domain.
  http://creativecommons.org/publicdomain/zero/1.0/
-->
<!DOCTYPE HTML>
<html>
<head>
</head>
<body>
<script type="text/javascript">

function wait_until_controlled() {
  return new Promise(function(resolve) {
    if (navigator.serviceWorker.controller) {
      return resolve();
    }
    navigator.serviceWorker.addEventListener('controllerchange', function onController() {
      if (navigator.serviceWorker.controller) {
        navigator.serviceWorker.removeEventListener('controllerchange', onController);
        return resolve();
      }
    });
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}
addEventListener('load', function(event) {
  var registration;
  navigator.serviceWorker.register('worker.js').then(function(swr) {
    registration = swr;

    // While the iframe below is a navigation, we still wait until we are
    // controlled here.  We want an active client to hold the service worker
    // alive since it calls unregister() on itself.
    return wait_until_controlled();

  }).then(function() {
    var frame = document.createElement('iframe');
    document.body.appendChild(frame);
    frame.src = 'fake_download';

    // The service worker is unregistered in the fetch event.  The window and
    // frame are cleaned up from the browser chrome script.
  });
});
</script>
</body>
</html>
