chromium/chrome/test/data/extensions/api_test/automation/sites/force_layout.html

<!--
Copyright 2019 The Chromium Authors
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->
<html>
<head>
<title>Automation Tests - Force Layout</title>
</head>
<body>
<p>Test</p>
<button></button>
<script>
  let button = document.body.querySelector('button');
  button.addEventListener('focus', () => {
    button.style.display = 'none';
    button.style.width = 200;
    button.style.display = 'block';
  });
</script>
</body>
</html>