diff --git a/layout/svg/base/src/nsSVGImageFrame.cpp b/layout/svg/base/src/nsSVGImageFrame.cpp
index 9a2cd3205d6e..07e1eeb83dd2 100644
--- a/layout/svg/base/src/nsSVGImageFrame.cpp
+++ b/layout/svg/base/src/nsSVGImageFrame.cpp
@@ -52,7 +52,7 @@ using namespace mozilla;
 
 class nsSVGImageFrame;
 
-class nsSVGImageListener : public nsStubImageDecoderObserver
+class nsSVGImageListener MOZ_FINAL : public nsStubImageDecoderObserver
 {
 public:
   nsSVGImageListener(nsSVGImageFrame *aFrame);