diff --git a/dom/svg/nsSVGFilters.cpp b/dom/svg/nsSVGFilters.cpp
index 953055a23881..c677156c9e79 100644
--- a/dom/svg/nsSVGFilters.cpp
+++ b/dom/svg/nsSVGFilters.cpp
@@ -502,7 +502,7 @@ nsSVGFELightingElement::ComputeLightAttributes(nsSVGFilterInstance* aInstance)
 }
 
 FilterPrimitiveDescription
-nsSVGFELightingElement::AddLightingAttributes(const FilterPrimitiveDescription& aDescription,
+nsSVGFELightingElement::AddLightingAttributes(FilterPrimitiveDescription aDescription,
                                               nsSVGFilterInstance* aInstance)
 {
   nsIFrame* frame = GetPrimaryFrame();
@@ -523,7 +523,7 @@ nsSVGFELightingElement::AddLightingAttributes(const FilterPrimitiveDescription&
     return FilterPrimitiveDescription(PrimitiveType::Empty);
   }
 
-  FilterPrimitiveDescription descr = aDescription;
+  FilterPrimitiveDescription& descr = aDescription;
   descr.Attributes().Set(eLightingLight, ComputeLightAttributes(aInstance));
   descr.Attributes().Set(eLightingSurfaceScale, surfaceScale);
   descr.Attributes().Set(eLightingKernelUnitLength, kernelUnitLength);
diff --git a/dom/svg/nsSVGFilters.h b/dom/svg/nsSVGFilters.h
index 8665afb4c528..4d845b244ac4 100644
--- a/dom/svg/nsSVGFilters.h
+++ b/dom/svg/nsSVGFilters.h
@@ -202,7 +202,7 @@ protected:
   AttributeMap ComputeLightAttributes(nsSVGFilterInstance* aInstance);
 
   FilterPrimitiveDescription
-    AddLightingAttributes(const FilterPrimitiveDescription& aDescription,
+    AddLightingAttributes(FilterPrimitiveDescription aDescription,
                           nsSVGFilterInstance* aInstance);
 
   enum { SURFACE_SCALE, DIFFUSE_CONSTANT, SPECULAR_CONSTANT, SPECULAR_EXPONENT };