SVG - support radialGradient fr attribute

layout/reftests/svg/radialGradient-fr-02-ref.svg

@@ -0,0 +1,28 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:xlink="http://www.w3.org/1999/xlink">
+  <title>Test gradient fr attribute</title>
+  <defs>
+    <radialGradient id="grad1">
+      <stop offset="0%" stop-color="red" />
+      <stop offset="20%" stop-color="red" />
+      <stop offset="100%" stop-color="lime" />
+    </radialGradient>
+    <style>
+      .cover {
+        stroke-width: 3px;
+        stroke: lime;
+        fill: none;
+        image-rendering: optimizeSpeed;
+      }
+    </style>
+  </defs>
+  <rect width="100%" height="100%" fill="lime"/>
+
+  <circle cx="100" cy="100" r="50" fill="url(#grad1)" />
+  <circle class="cover" cx="100" cy="100" r="50" fill="none"/>
+</svg>
+