LayoutTests/compositing/repaint/scroll-fixed-layer-out-of-view.html - WebKit - Git at Google

 <!DOCTYPE html>
 <html>
 <head>
     <script type="text/javascript">
         if (window.testRunner)
             testRunner.dumpAsText();

         if (window.internals) {
             internals.settings.setAcceleratedCompositingForFixedPositionEnabled(true);
             internals.settings.setFixedPositionCreatesStackingContext(true);
         }

         function test()
         {
             document.body.offsetHeight;
             if (window.internals)
                 window.internals.startTrackingRepaints(document);

             window.scrollTo(0, 1000);
             window.scrollTo(0, 100);

             if (window.internals)
                 document.getElementById('repaintRects').textContent = window.internals.repaintRectsAsText(document);
         }
     </script>
 </head>
 <body style="height:2000px" onload="test()">
     <div style="position: fixed; top: -300px; left: 100px; width: 88px; height: 88px; background-color: silver"></div>
     <div style="position: fixed; top: 1000px; left: 100px; width: 99px; height: 99px; background-color: silver"></div>
     There should be no repaints here:
     <pre id="repaintRects"></pre>
 </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<script type="text/javascript">
	if (window.testRunner)
	testRunner.dumpAsText();

	if (window.internals) {
	internals.settings.setAcceleratedCompositingForFixedPositionEnabled(true);
	internals.settings.setFixedPositionCreatesStackingContext(true);
	}

	function test()
	{
	document.body.offsetHeight;
	if (window.internals)
	window.internals.startTrackingRepaints(document);

	window.scrollTo(0, 1000);
	window.scrollTo(0, 100);

	if (window.internals)
	document.getElementById('repaintRects').textContent = window.internals.repaintRectsAsText(document);
	}
	</script>
	</head>
	<body style="height:2000px" onload="test()">
	<div style="position: fixed; top: -300px; left: 100px; width: 88px; height: 88px; background-color: silver"></div>
	<div style="position: fixed; top: 1000px; left: 100px; width: 99px; height: 99px; background-color: silver"></div>
	There should be no repaints here:
	<pre id="repaintRects"></pre>
	</body>
	</html>