LayoutTests/imported/blink/http/tests/security/mixedContent/resources/frame-with-insecure-eventsource.html

<script>
var es = new EventSource("http://127.0.0.1:8000/eventsource/resources/simple-event-stream.asis");

window.onload = function() {
    if (window.opener)
        window.opener.postMessage('done', '*');
};
</script>