See downstream https://phabricator.wikimedia.org/T232600.
This is a simplified document which freezes Chrome 77:
<html>
<head>
<style type="text/css">
.AAA {
width: 200px;
white-space: nowrap;
word-wrap: break-word;
}
.BBB {
white-space: normal;
}
</style>
</head>
<body>
<div class="AAA">
<span>X</span>
<a class="BBB">MMMMMMMMMMMMMMMMMMMMMMMMM</a>
</div>
</body>
</html>