chromium/chrome/test/data/extensions/api_test/executescript/frame_id/frames.html

<iframe srcdoc="same-origin srcdoc frame"></iframe>

<!-- Unique origin about:blank -->
<iframe sandbox="" src="about:blank"></iframe>

<iframe src="frame.html"></iframe>

<script>
document.write('<iframe src="http://c.com:' + location.port +
               '/empty.html"></iframe>');
</script>