diff --git a/dom/svg/SVGSymbolElement.cpp b/dom/svg/SVGSymbolElement.cpp
index b0025d2f28e4..71ba2199e008 100644
--- a/dom/svg/SVGSymbolElement.cpp
+++ b/dom/svg/SVGSymbolElement.cpp
@@ -42,44 +42,6 @@ SVGSymbolElement::~SVGSymbolElement()
 
 NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGSymbolElement)
 
-//----------------------------------------------------------------------
-
-already_AddRefed<SVGAnimatedRect>
-SVGSymbolElement::ViewBox()
-{
-  return mViewBox.ToSVGAnimatedRect(this);
-}
-
-already_AddRefed<DOMSVGAnimatedPreserveAspectRatio>
-SVGSymbolElement::PreserveAspectRatio()
-{
-  return mPreserveAspectRatio.ToDOMAnimatedPreserveAspectRatio(this);
-}
-
-//----------------------------------------------------------------------
-// nsIContent methods
-
-NS_IMETHODIMP_(bool)
-SVGSymbolElement::IsAttributeMapped(const nsIAtom* name) const
-{
-  static const MappedAttributeEntry* const map[] = {
-    sColorMap,
-    sFEFloodMap,
-    sFillStrokeMap,
-    sFiltersMap,
-    sFontSpecificationMap,
-    sGradientStopMap,
-    sGraphicsMap,
-    sLightingEffectsMap,
-    sMarkersMap,
-    sTextContentElementsMap,
-    sViewportsMap
-   };
-
-  return FindAttributeDependence(name, map) ||
-    SVGSymbolElementBase::IsAttributeMapped(name);
-}
-
 //----------------------------------------------------------------------
 // SVGTests methods
 
@@ -89,21 +51,5 @@ SVGSymbolElement::IsInChromeDoc() const
   return nsContentUtils::IsChromeDoc(OwnerDoc());
 }
 
-
-//----------------------------------------------------------------------
-// nsSVGElement methods
-
-nsSVGViewBox *
-SVGSymbolElement::GetViewBox()
-{
-  return &mViewBox;
-}
-
-SVGAnimatedPreserveAspectRatio *
-SVGSymbolElement::GetPreserveAspectRatio()
-{
-  return &mPreserveAspectRatio;
-}
-
 } // namespace dom
-} // namespace mozilla
\ No newline at end of file
+} // namespace mozilla
diff --git a/dom/svg/SVGSymbolElement.h b/dom/svg/SVGSymbolElement.h
index 9c7bd809f216..cfc21e9d0da4 100644
--- a/dom/svg/SVGSymbolElement.h
+++ b/dom/svg/SVGSymbolElement.h
@@ -7,10 +7,7 @@
 #ifndef mozilla_dom_SVGSymbolElement_h
 #define mozilla_dom_SVGSymbolElement_h
 
-#include "mozilla/dom/SVGTests.h"
-#include "nsSVGElement.h"
-#include "nsSVGViewBox.h"
-#include "SVGAnimatedPreserveAspectRatio.h"
+#include "SVGViewportElement.h"
 
 nsresult NS_NewSVGSymbolElement(nsIContent **aResult,
                                 already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
@@ -18,10 +15,9 @@ nsresult NS_NewSVGSymbolElement(nsIContent **aResult,
 namespace mozilla {
 namespace dom {
 
-typedef nsSVGElement SVGSymbolElementBase;
+typedef SVGViewportElement SVGSymbolElementBase;
 
-class SVGSymbolElement final : public SVGSymbolElementBase,
-                               public SVGTests
+class SVGSymbolElement final : public SVGSymbolElementBase
 {
 protected:
   friend nsresult (::NS_NewSVGSymbolElement(nsIContent **aResult,
@@ -32,31 +28,16 @@ protected:
 
 public:
   // interfaces:
-
   NS_DECL_ISUPPORTS_INHERITED
 
-  // nsIContent interface
-  NS_IMETHOD_(bool) IsAttributeMapped(const nsIAtom* name) const override;
-
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
                          bool aPreallocateChildren) const override;
 
-  // WebIDL
-  already_AddRefed<SVGAnimatedRect> ViewBox();
-  already_AddRefed<DOMSVGAnimatedPreserveAspectRatio> PreserveAspectRatio();
-
   // SVGTests
   bool IsInChromeDoc() const override;
-
-protected:
-  virtual nsSVGViewBox *GetViewBox() override;
-  virtual SVGAnimatedPreserveAspectRatio *GetPreserveAspectRatio() override;
-
-  nsSVGViewBox mViewBox;
-  SVGAnimatedPreserveAspectRatio mPreserveAspectRatio;
 };
 
 } // namespace dom
 } // namespace mozilla
 
-#endif // mozilla_dom_SVGSymbolElement_h
\ No newline at end of file
+#endif // mozilla_dom_SVGSymbolElement_h