Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/fast/frames/resources/sandboxed-iframe-about-blank.html 

<html>
<head>
</head>
<body>
    <iframe src="about:blank" sandbox>
    </iframe>
    <script>
    parent.testPassed("Container frame is able to run script.");
    </script>
</body>
</html>