<!DOCTYPE html> <!-- webkit-test-runner [ internal:AsyncOverflowScrollingEnabled=true ] -->
<html>
<head>
    <style>
		#scroller {
			position: relative;
			overflow-y: scroll;
			width: 300px;
			height: 300px;
			border: 1px solid black;
		}

		.negative {
			position: relative;
			z-index: -1;
			margin: 20px;
		    width: 200px;
		    height: 200px;
		    background-color: green;
		}

        .spacer {
            height: 1000px;
            width: 10px;
            background-color: silver;
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.dumpAsText();

        window.addEventListener('load', () => {
            if (window.internals)
                document.getElementById('layers').innerText = window.internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_CLIPPING);
        }, false);
    </script>
</head>
<body>
	<div id="scroller">
        <div class="negative box"></div>
        <div class="spacer"></div>
	</div>
<pre id="layers"></pre>
</body>
</html>