<script>
function runRepaintTest() {

if (window.testRunner)
    testRunner.waitUntilDone();

setTimeout(function() {
    let shrink = document.getElementById("subpixel_iframe").contentDocument.getElementById("shrink");
    if (!window.testRunner) {
        setTimeout('shrink.style.height = "0px"', 100);
        return;
    }

    testRunner.dumpAsText();
    document.body.offsetTop;
    internals.startTrackingRepaints();

    shrink.style.height = "0px";
    document.getElementById("subpixel_iframe").contentDocument.body.offsetHeight;

    let layerTreeAsText = window.internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_REPAINT_RECTS);
    internals.stopTrackingRepaints();

    let pre = document.createElement('pre');
    document.body.appendChild(pre);
    pre.innerHTML = layerTreeAsText;
    testRunner.notifyDone();
}, 0);

}
</script>
<style>
.container {
  position: fixed;
  left: 0px;
  top: 0px;
  padding: 0.5px;
}
</style>
<body>
<div class=container><div><iframe onload="runRepaintTest()" id=subpixel_iframe frameborder=no srcdoc="
<style>
body {
  margin:0px;
}
div {
  background-color: green;
  height: 100px;
  width: 100px;
}
</style>
<div id=shrink></div>">
</body>