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chromium/third_party/blink/web_tests/fast/parser/script-modify-page-outer.html 

<!DOCTYPE html>
<html>
<script>

if (window.testRunner)
    testRunner.dumpAsText();

</script>
<body onload="document.body.appendChild(document.createTextNode('DONE'));">
<iframe src="resources/script-modify-page-inner.html"></iframe>
</body>
</html>