LayoutTests/fast/block/line-clamp-collapse-nested-blocks.html

<style>
.container {
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden; 
}
</style>
<div class=container>
  <div>
    <div>PASS if this is visible</div>
  second line
</div>