<!DOCTYPE html>
<style>
.focus {
  position: absolute;
  top: 50.5px;
  left: 10.5px;
  width: 100.6px;
  outline: -webkit-focus-ring-color auto 5px;
}
.layer {
  position: relative;
  height: 20px;
}
</style>
Tests focus ring around sub-pixel positioned and sized element containing layers.
The focus ring should be rectangular.
<div class="focus">
  Text
  <div class="layer"></div>
</div>
