LayoutTests/svg/css/mask-with-shadow.svg

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN"
"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" id="body" width="450" height="500" viewBox="0 0 450 500">

    <g>

        <defs>

        <linearGradient id="maskedGradient" x1="0" x2="1" y1="0" y2="1" color-interpolation="linearRGB">
            <stop offset="0" stop-color="blue" />
            <stop offset="1" stop-color="red" />
        </linearGradient>

        <rect id="masked" width="300" height="300" fill="url(#maskedGradient)" />

        <mask id="mask_1" style="-webkit-svg-shadow:5px 5px 5px grey">
            <circle cx="55" cy="55" r="50" fill="#ffffff" />
            <circle cx="55" cy="165" r="50" fill="#ffffff" />
            <circle cx="165" cy="55" r="50" fill="#ffffff" />
            <circle cx="165" cy="165" r="50" fill="#ffffff" />
        </mask>

     
        </defs>


        <g>
            <use xlink:href="#masked" mask="url(#mask_1)"/>
        </g>
    </g>
    
</svg>