SVG Linear Gradient does not work in Firefox

This issue is fixed from Firefox 77 onwards. To workaround the problem in earlier versions of Firefox, simply move the gradient definition outside the symbol element e.g.

<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
 width="30px" height="35px" viewBox="0 0 30 35" enable-background="new 0 0 30 35" xml:space="preserve">
        <defs>
          <linearGradient id="SVGID_1_" gradientUnits="userSpaceOnUse" x1="7" y1="-13" x2="7" y2="1">
            <stop  offset="0" stop-color="#0000FF"/>
            <stop  offset="1" style="stop-color:#00FF00"/>
          </linearGradient>
        </defs>
<symbol  id="replay_icon" viewBox="0 -12 14 12">
    <g id="Layer_1_2_">
        <path fill-rule="evenodd" clip-rule="evenodd" fill="url(#SVGID_1_)" d="M12.25-10.25C11.083-11.417,9.667-12,8-12v2
            c1.1,0,2.05,0.383,2.85,1.15C11.617-8.083,12-7.133,12-6c0,1.1-0.383,2.033-1.15,2.8C10.05-2.4,9.1-2,8-2S5.95-2.4,5.15-3.2
            C4.383-3.967,4-4.883,4-5.95h2l-3-4l-3,4h2c0,1.633,0.583,3.034,1.75,4.2S6.333,0,8,0s3.083-0.583,4.25-1.75S14-4.333,14-6
            S13.417-9.083,12.25-10.25z"/>
    </g>
</symbol>
<use xlink:href="#replay_icon"  width="14" height="12" y="-12" transform="matrix(1 0 0 -1 10 11)" overflow="visible"/>
</svg>