LayoutTests/fast/block/float/zero-margin-box-float-overlap-expected.html

<style>
.container {
  margin: 200px;
  height: 300px;
  width: 500px;
}
.content {
  margin-left: -50px;
  margin-right: -50px;
  overflow: hidden;
  height: 50px;
  background-color: green;
}
</style>
<div class=container><div class=content></div></div>