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chromium/third_party/blink/web_tests/http/tests/security/create-document-unique-origin.html 

<!DOCTYPE html>
<script>
if (window.testRunner)
    testRunner.dumpAsText();
</script>
<iframe sandbox='allow-scripts' srcdoc='<script>var d = document.implementation.createHTMLDocument("");d.open();console.log("SUCCESS");</script>'></iframe>