chromium/chrome/test/data/printing/loop_child_iframe.html

<!DOCTYPE html>
<html>
  <head>
    <title>A child frame of an iframe</title>
  <head>
  <body>
    <p>
    This is a test page.
    </p>
    <div>
      <iframe id="iframe-child" src="/cross-site/a.com/printing/test1.html" style="height:250px; margin:0px; padding:0px">
      </iframe>
  </body>
</html>