LayoutTests/fast/inline/overflowing-content-inside-inline-box.html

<style>
div {
  width: 0px;
  word-break: break-word;
  font-family: Ahem;
}

span {
  border: 1px solid green;
}
</style>
<div><span>X</span><span>X</span><span>X</span></div>