<!DOCTYPE html>
<html>
<head>
<style>
div {
    white-space: pre-line;
    padding-bottom: 10px;
    font-size: 20px;
    font-family: ahem;
    border: 1px solid blue;
}
</style>
<script>
if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.waitUntilDone();
}
</script>
</head>
<body>
<div id="text">foo
bar</div>
<script>
document.body.offsetWidth;
setTimeout(function() {
    if (window.internals)
        internals.startTrackingRepaints();
    document.getElementById('text').innerHTML = "foo";
    if (window.internals) {
        let repaintRects = internals.repaintRectsAsText();
        internals.stopTrackingRepaints();

        let pre = document.createElement('pre');
        document.body.appendChild(pre);
        pre.innerHTML = repaintRects;
        testRunner.notifyDone();
    }
}, 10);
</script>
</body>
</html>