chromium/chrome/test/data/iframe_out_of_view.html

<!DOCTYPE html>
<html>
<body>
  <style>
  body {
    width: 100%;
    height: 100%;
    margin: 0;
  }

  iframe {
    width: 400px;
    height: 400px;
    /* The size of the margin is bigger than the viewport */
    margin: 300%;
    border: 0;
    padding: 0;
    overflow: scroll;
  }
  </style>
  <p> Single &lt;iframe&gt; which is positioned out of view. </p>
  <iframe src="title1.html">
  </iframe>
  <p> Iframe should be positioned way above </p>
</body>
</html>