chromium/third_party/blink/web_tests/screen_orientation/resources/sandboxed-iframe-locking.html

<!DOCTYPE html>
<html>
<script>
    var msg = "";
    screen.orientation.lock("portrait-primary").then(function() {
    }, function(error) {
        msg = error.name;
    });

    // FIXME: for the moment, tests gets notified when there is a failure but
    // not a success, this hack should allow us to still have the test running.
    // That should be removed as soon as we get a resolved promise in tests.
    setTimeout(function() {
        parent.window.postMessage(msg, "*");
    })
</script>
</html>