third_party/WebKit/LayoutTests/fast/hidpi/image-set-background-dynamic.html - chromium/src - Git at Google

 <!DOCTYPE html>
 <script src="resources/srcset-helper.js"></script>
 <style>
     #foo {
         width:100px;
         height:100px;
         background-image: -webkit-image-set(url('resources/blue-100-px-square.png') 1x, url('resources/green-400-px-square.png') 2x);
     }
 </style>
 <div>This test passes if the div below is a blue 100px square when the deviceScaleFactor is 1, and if it is a 100px green square when the deviceScaleFactor is 2. When run in the test harness, this test is distinct from image-set-as-background, because it ensures that the green image loads dynamically when the scale factor changes.</div>
 <div id=foo></div>
	<!DOCTYPE html>
	<script src="resources/srcset-helper.js"></script>
	<style>
	#foo {
	width:100px;
	height:100px;
	background-image: -webkit-image-set(url('resources/blue-100-px-square.png') 1x, url('resources/green-400-px-square.png') 2x);
	}
	</style>
	<div>This test passes if the div below is a blue 100px square when the deviceScaleFactor is 1, and if it is a 100px green square when the deviceScaleFactor is 2. When run in the test harness, this test is distinct from image-set-as-background, because it ensures that the green image loads dynamically when the scale factor changes.</div>
	<div id=foo></div>