LayoutTests/fast/scrolling/programmatic-scroll-to-zero-zero.html - WebKit - Git at Google

 <!DOCTYPE html>
 <html>
 <head>
     <title>The page should scroll back to the top</title>
     <style>
         body {
             height: 2000px;
             background-image: repeating-linear-gradient(white, silver 200px);
         }

         .box {
             width: 100px;
             height: 100px;
             background-color: green;
         }
     </style>
     <script>
 		if (window.testRunner)
             testRunner.waitUntilDone();

 		function doTest()
         {
             document.scrollingElement.scrollTop = 20;
             document.scrollingElement.scrollTop = 0;

             eventSender.monitorWheelEvents();

             setTimeout(() => {
                 eventSender.mouseMoveTo(20, 20);
                 eventSender.mouseScrollByWithWheelAndMomentumPhases(0, -1, "began", "none");
                 eventSender.mouseScrollByWithWheelAndMomentumPhases(0, -10, "changed", "none");
                 eventSender.mouseScrollByWithWheelAndMomentumPhases(0, 0, "ended", "none");
                 eventSender.callAfterScrollingCompletes(() => {
                     document.scrollingElement.scrollTop = 0;
                     testRunner.notifyDone();
                 });
             }, 0);
         }

         window.addEventListener('load', doTest, false);
     </script>
 </head>
 <body>
     <div class="box"></div>
 </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<title>The page should scroll back to the top</title>
	<style>
	body {
	height: 2000px;
	background-image: repeating-linear-gradient(white, silver 200px);
	}

	.box {
	width: 100px;
	height: 100px;
	background-color: green;
	}
	</style>
	<script>
	if (window.testRunner)
	testRunner.waitUntilDone();

	function doTest()
	{
	document.scrollingElement.scrollTop = 20;
	document.scrollingElement.scrollTop = 0;

	eventSender.monitorWheelEvents();

	setTimeout(() => {
	eventSender.mouseMoveTo(20, 20);
	eventSender.mouseScrollByWithWheelAndMomentumPhases(0, -1, "began", "none");
	eventSender.mouseScrollByWithWheelAndMomentumPhases(0, -10, "changed", "none");
	eventSender.mouseScrollByWithWheelAndMomentumPhases(0, 0, "ended", "none");
	eventSender.callAfterScrollingCompletes(() => {
	document.scrollingElement.scrollTop = 0;
	testRunner.notifyDone();
	});
	}, 0);
	}

	window.addEventListener('load', doTest, false);
	</script>
	</head>
	<body>
	<div class="box"></div>
	</body>
	</html>