<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true ] -->
<html>
<head>
    <title>Tests an overflow scroll stops compositing if its content shrinks</title>
    <style>
        .scrollable {
            overflow-y: scroll;
            height: 300px;
            width: 300px;
            margin: 10px;
            border: 1px solid black;
        }
    
        .contents {
            height: 500px;
            width: 20px;
            background-color: silver;
        }
        
        .contents.changed {
            height: 100px;
        }
    </style>
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.waitUntilDone();
        }

        window.addEventListener('load', () => {
            setTimeout(() => {
                document.querySelector('.contents').classList.add('changed');

                if (window.internals)
                    document.getElementById('layers').innerText = window.internals.layerTreeAsText(document);

                if (window.testRunner)
                    testRunner.notifyDone();
            }, 0);
        }, false);
    </script>
</head>
<body>
    <div class="scrollable">
        <div class="contents"></div>
    </div>
<p>There should be no layers.</p>
<pre id="layers"></pre>
</body>
</html>