chromium/components/test/data/ads_observer/same_origin_ad.html

<html>
<body>
<script src="ad_iframe_writer.js"></script>

<!-- Should be counted as a normal same-origin ad iframe. -->
<script>
    let adIframe = createAdIframe();
    adIframe.id = "src_frame_same_origin";
    adIframe.src = "pixel.png"
</script>

</body>
</html>