<script>
function test() {
    if (window.internals)
        internals.settings.setLegacyLineLayoutVisualCoverageEnabled(true);
    var target = document.getElementById("target");
    eventSender.mouseMoveTo(target.offsetLeft + 5, target.offsetTop + 5);
}
</script>
<body onload="test()">
<div id="target">This text should not have legacy line layout visual indicator.</div>