<!DOCTYPE html>
<html>
<body>
<div id=foobar style="width: 100px; height: 100px;"></div>
<script>
let foobarWidth = 200;
testRunner.waitUntilDone();
testRunner.forceLayout();

setInterval(function() {
    foobar.style.width = foobarWidth + "px";
    testRunner.forceLayout();
    foobarWidth += 50;
}, 10);

setTimeout(function() {
    testRunner.notifyDone();
}, 500);
</script>
</body>
</html>