Bug 1319667 - (follow-up) Remove incorrect assertion. r=me

If the size of mask is empty, we wil hit this assertion, which is wrong.

MozReview-Commit-ID: LgulkGPsjyH

--HG--
extra : rebase_source : fbf8fc05a0bfa16b28599726f8ee85d4468d5d86

layout/svg/nsSVGIntegrationUtils.cpp

@@ -892,7 +892,6 @@ nsSVGIntegrationUtils::PaintMaskAndClipPath(const PaintFramesParams& aParams)
                                   maskFrames, offsetToUserSpace);
 
       if (paintResult.transparentBlackMask) {
-        MOZ_ASSERT(paintResult.result != DrawResult::SUCCESS);
         return paintResult.result;
       }