chromium/content/test/data/accessibility/html/frame/button_scrolled.html

<!DOCTYPE html>
<html>
<body style="margin: 0; padding: 0;">
<div style="width: 300px; height: 100px;">
  <button style="margin: 25px; border: 0; width: 250px; height: 50px">
    Unscrolled Button
  </button>
</div>
<script>
  window.scrollTo(150, 50);
  document.querySelector('button').textContent = 'Scrolled Button';
</script>
</body>
</html>