LayoutTests/fast/repaint/layout-state-scrolloffset2.html - WebKit - Git at Google

 <!DOCTYPE html>
 <html>
 <body>
   You should see the text 'after' in the inner box, no mangled pixels.
   <div id="parent1" style="position:absolute; width:300px; height:300px; overflow:hidden; border: solid 1px yellow">
     <div id="parent2" style="position:absolute; width:300px; height:300px; overflow:hidden; border: solid 1px red">
       <div style="position:absolute; width:100px; height:100px; left:100px; top:100px; border:solid 1px green; overflow:hidden">
         <div id="target" style="width:50px; height:50px">before</div>
       </div>
       <div style="width:1000px; height:1000px;"></div>
     </div>
   </div>
 </body>
 <script>
   parent1 = document.getElementById('parent1');
   parent1.scrollTop = 7;
   parent1.scrollLeft = 7;

   parent2 = document.getElementById('parent2');
   parent2.scrollTop = 7;
   parent2.scrollLeft = 7;

   if (window.testRunner)
     testRunner.waitUntilDone();

   window.setTimeout(function() {
     if (window.testRunner)
       testRunner.display();

     document.getElementById('target').innerText = 'after'

     if (window.testRunner)
       testRunner.notifyDone();
   }, 50);
 </script>
 </html>
	<!DOCTYPE html>
	<html>
	<body>
	You should see the text 'after' in the inner box, no mangled pixels.
	<div id="parent1" style="position:absolute; width:300px; height:300px; overflow:hidden; border: solid 1px yellow">
	<div id="parent2" style="position:absolute; width:300px; height:300px; overflow:hidden; border: solid 1px red">
	<div style="position:absolute; width:100px; height:100px; left:100px; top:100px; border:solid 1px green; overflow:hidden">
	<div id="target" style="width:50px; height:50px">before</div>
	</div>
	<div style="width:1000px; height:1000px;"></div>
	</div>
	</div>
	</body>
	<script>
	parent1 = document.getElementById('parent1');
	parent1.scrollTop = 7;
	parent1.scrollLeft = 7;

	parent2 = document.getElementById('parent2');
	parent2.scrollTop = 7;
	parent2.scrollLeft = 7;

	if (window.testRunner)
	testRunner.waitUntilDone();

	window.setTimeout(function() {
	if (window.testRunner)
	testRunner.display();

	document.getElementById('target').innerText = 'after'

	if (window.testRunner)
	testRunner.notifyDone();
	}, 50);
	</script>
	</html>