chromium/third_party/blink/web_tests/fast/preloader/iframe-srcdoc.html

<body>
<script>
    if (window.testRunner) {
        testRunner.dumpChildFrames();
        testRunner.dumpAsText();
    }

</script>
This test has to be run using `ContentShell --run-web-tests` in order to see if resources were loaded and the test passed.
<iframe srcdoc="<script> window.addEventListener('DOMContentLoaded', function() { if (window.internals) console.log(internals.isPreloaded('resources/script1.js') ? 'PASS' : 'FAIL'); }, false); </script><script src=resources/non-existant.js></script><script>document.write('<plaintext>');</script> <script src=resources/script1.js></script>" />