<!DOCTYPE html>
<iframe id="target" style="border-radius: 20px"
        srcdoc="<div style='width: 300px; height:400px; background: blue'>"></iframe>
<script src="../../../resources/testharness.js"></script>
<script src="../../../resources/testharnessreport.js"></script>
<script src="../../../resources/run-after-layout-and-paint.js"></script>
<script>
if (window.internals)
  internals.settings.setPreferCompositingToLCDTextEnabled(true);
onload = () => {
  async_test(t => {
    runAfterLayoutAndPaint(t.step_func_done(() => {
      target.style.height = "600px";
    }));
  });
};
</script>