<!DOCTYPE html>
<style>
#container {
    text-indent: -300px;
    width: 300px;
}

</style>
<p>crbug.com/627149: Collapse away nested anonymous blocks. There should be no text below.</p>
<button id="container">
    <span id="span">Text.</span>
</button>
<script>
    var container = document.getElementById('container');
    var div = document.createElement('div');
    container.insertBefore(div, document.getElementById('span'));
    document.body.offsetTop;
    container.removeChild(div);
</script>