LayoutTests/tiled-drawing/fixed-background-scroll-repaint.html - WebKit - Git at Google

 <!DOCTYPE html>

 <html>
 <head>
     <style>
         body {
             height: 2000px;
         }
  	   #test {
  	       height: 200px;
  	       width: 250px;
  	       border: 1px solid black;
  	       background-image: linear-gradient(blue, green);
  	       background-size: 100% 300px;
            background-attachment: fixed;
  	   }
     </style>
     <script>
         if (window.testRunner) {
             testRunner.dumpAsText();
             testRunner.waitUntilDone();
         }

         function documentLoaded()
         {
             // Timeout is required to allow layers to paint before the scroll.
             window.setTimeout(doTest, 0);
         }

         function doTest()
         {
             if (window.internals)
                 window.internals.startTrackingRepaints();

             window.scrollTo(0, 100);

             if (window.internals)
                 document.getElementById('repaintRects').textContent = window.internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_REPAINT_RECTS);

             if (window.testRunner)
                 testRunner.notifyDone();
         }

         window.addEventListener('load', documentLoaded, false);
     </script>
 </head>
 <body>

 <p>We should only repaint the bounds of the element with a fixed background.</p>
 <div id="test"></div>
 <pre id="repaintRects"></pre>

 </body>
 </html>
	<!DOCTYPE html>

	<html>
	<head>
	<style>
	body {
	height: 2000px;
	}
	#test {
	height: 200px;
	width: 250px;
	border: 1px solid black;
	background-image: linear-gradient(blue, green);
	background-size: 100% 300px;
	background-attachment: fixed;
	}
	</style>
	<script>
	if (window.testRunner) {
	testRunner.dumpAsText();
	testRunner.waitUntilDone();
	}

	function documentLoaded()
	{
	// Timeout is required to allow layers to paint before the scroll.
	window.setTimeout(doTest, 0);
	}

	function doTest()
	{
	if (window.internals)
	window.internals.startTrackingRepaints();

	window.scrollTo(0, 100);

	if (window.internals)
	document.getElementById('repaintRects').textContent = window.internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_REPAINT_RECTS);

	if (window.testRunner)
	testRunner.notifyDone();
	}

	window.addEventListener('load', documentLoaded, false);
	</script>
	</head>
	<body>

	<p>We should only repaint the bounds of the element with a fixed background.</p>
	<div id="test"></div>
	<pre id="repaintRects"></pre>

	</body>
	</html>