<!doctype HTML>
<div style="-webkit-mask-image: url(../../fast/backgrounds/resources/mask-top-left.png); width: 200px; height: 200px; background: blue">
</div>
<!doctype HTML>
<div style="-webkit-mask-image: url(../../fast/backgrounds/resources/mask-top-left.png); width: 200px; height: 200px; background: blue">
</div>