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chromium/components/test/data/subresource_filter/frame_cross_site_set.html 

<html>
  <body>
    <iframe name="b" src="/cross-site/b.com/subresource_filter/frame_with_included_script.html"></iframe>
    <iframe name="c" src="/cross-site/c.com/subresource_filter/frame_d.html"></iframe>
  </body>
</html>