LayoutTests/fullscreen/enter-fullscreen-main-frame-window-open-iframe.html

<p>To test manually, click the "Open window" button - the page should exit fullscreen mode.</p>
<script src="full-screen-test.js"></script>
<script>
function runTest() {
    waitForEventOnce(document, 'fullscreenchange', function() {
        test("document.fullscreenElement===document.body")
        waitForEventOnce(document, 'fullscreenchange', function() {
            test("document.fullscreenElement===null")
            endTest();
        });
        document.getElementById("frame").contentWindow.exitFullscreen();
    });

    runWithKeyDown(function() {
        document.body.requestFullscreen();
    });
}
</script>
<iframe id="frame" src="resources/window-open-iframe.html" width="300" height="100" onload="runTest()">
</iframe>