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chromium/third_party/blink/web_tests/fast/block/positioning/fixed-position-detached-frame.html 

<!DOCTYPE html>
<iframe></iframe>
<script>
framedoc = frames[0].document.documentElement;
document.body.innerText = 'PASS';
framedoc.innerHTML = '<title style="position:fixed">';
framedoc.getElementsByTagName('title')[0].innerText = 'a';
if (window.testRunner)
    testRunner.dumpAsText()
</script>