<!DOCTYPE html>
<style>
/* RenderObject::objectIsRelayoutBoundary() should be true */
#relayoutBoundary {
    overflow: hidden;
    width: 100px;
    height: 100px;
}
</style>
<div id="relayoutBoundary">
    <div id="layouter"></div>
</div>
<script>
document.body.offsetTop;
document.getElementById("layouter").style.position = "relative";
document.body.offsetTop;
</script>