LayoutTests/fast/layoutformattingcontext/block-only/block-root-top-should-start-from-float-top.html

<!-- webkit-test-runner [ internal:LayoutFormattingContextEnabled=true internal:LayoutFormattingContextIntegrationEnabled=false ] -->
<style>
.left {
  float: left;
  width: 100px;
  height: 40px;
}

.avoider {
  width: auto;
  height: 60px;
}
</style>
<div style="background-color: green; width: 300px; overflow: hidden;">
  <div class=left></div>
  <div class=avoider style="clear: left"></div>
  <div class=left style="height: 300px"></div>
</div>