<!DOCTYPE html> <!-- webkit-test-runner [ useFlexibleViewport=true AsyncOverflowScrollingEnabled=true ] -->
<html>
<head>
    <meta name="viewport" content="initial-scale=1.0">
    <style>
        #scroller {
            margin: 10px;
            height: 300px;
            width: 300px;
            border: 1px solid black;
            overflow: scroll;
        }
        
        .box {
            position: relative;
            z-index: 0; /* stacking context ancestor is the root */
            top: 250px;
            width: 200px;
            height: 200px;
            background-color: blue;
        }
        
        .scroll-content {
            height: 2000px;
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.waitUntilDone();

        function getUnstableScrollScript(x, y, scrollX, scrollY)
        {
            return `(function() {
                uiController.scrollUpdatesDisabled = true;
                uiController.immediateScrollElementAtContentPointToOffset(${x}, ${y}, ${scrollX}, ${scrollY});
                uiController.doAfterPresentationUpdate(function() {
                    uiController.uiScriptComplete();
                });
            })();`;
        }

        function doTest()
        {
            if (!testRunner.runUIScript)
                return

            testRunner.runUIScript(getUnstableScrollScript(50, 50, 0, 250), () => {
                testRunner.notifyDone();
            });
        }
        
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>
    <div id="scroller">
        <div class="scroll-content">
            <div class="box"></div>
        </div>
    </div>
</body>
</html>