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chromium/third_party/blink/web_tests/fast/forms/state-restore-before-pageshow.html 

<!DOCTYPE html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="resources/utils.js"></script>
<body>
<iframe src="resources/state-restore-before-pageshow-frame.html"></iframe>
<script>
let promiseResolver = null;

promise_test(async t => {
  await waitForEvent(window, 'load', {once:true});
  const iframe = document.querySelector('iframe');
  let doc = iframe.contentDocument;

  // Change control state.
  doc.querySelector('select').value = 'o2';

  // Navigate in the frame
  iframe.src = 'data:text/html,<h1></h1>';
  await waitForEvent(iframe, 'load', {once:true});

  // Navigate back
  const valueOnPageShow = await new Promise((resolve, reject) => {
    window.promiseResolver = resolve;
    history.back();
  });
  assert_equals(valueOnPageShow, 'o2');
}, '');
</script>