block-mask-overlay-image.html | Explore in Territory

<head>
<style>
.blockTest {
         height:400px;
         padding:50px;
         color:white;
	 background-color:maroon;
         -webkit-mask-box-image: url(resources/mask.png) 75 75 75 75;
}
</style>
</head>
<body>
<div class="blockTest">This content should be masked with a soft glow.</div>

chromium/third_party/blink/web_tests/fast/borders/block-mask-overlay-image.html