diff -r 000000000000 -r 6474c204b198 layout/reftests/svg/objectBoundingBox-and-mask.svg
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/reftests/svg/objectBoundingBox-and-mask.svg	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,25 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<!-- From https://bugzilla.mozilla.org/show_bug.cgi?id=489151 -->
+
+<svg xmlns="http://www.w3.org/2000/svg">
+  <title>Test objectBoundingBox mask on element with ancestor transform</title>
+  <desc>
+    This test checks that the bbox calculation for an objectBoundingBox
+    mask is correctly getting the bbox in the userspace of the masked
+    element, and not it's bbox in an ancestor userspace or rootspace.
+  </desc>
+  <mask id="mask" maskUnits="objectBoundingBox" maskContentUnits="objectBoundingBox">
+    <rect x="0.5" width="0.5" height="1" fill="white"/>
+  </mask>
+  <rect width="100%" height="100%" fill="lime"/>
+  <rect x="100" width="100" height="100" fill="red"/>
+  <g transform="translate(-100,0)">
+    <g mask="url(#mask)">
+      <rect x="100" width="100" height="100" fill="red"/>
+      <rect x="200" width="100" height="100" fill="lime"/>
+    </g>
+  </g>
+</svg>