--- a/content/svg/content/src/Makefile.in
+++ b/content/svg/content/src/Makefile.in
@@ -60,16 +60,17 @@ CPPSRCS		= \
 		nsSVGRect.cpp \
 		nsSVGUnknownElement.cpp \
 		nsSVGViewBox.cpp \
 		SVGAElement.cpp \
 		SVGAltGlyphElement.cpp \
 		SVGAngle.cpp \
 		SVGAnimatedAngle.cpp \
 		SVGAnimatedBoolean.cpp \
+		SVGAnimatedLength.cpp \
 		SVGAnimatedLengthList.cpp \
 		SVGAnimatedNumberList.cpp \
 		SVGAnimatedPathSegList.cpp \
 		SVGAnimatedPointList.cpp \
 		SVGAnimatedPreserveAspectRatio.cpp \
 		SVGAnimatedTransformList.cpp \
 		SVGAnimateElement.cpp \
 		SVGAnimateTransformElement.cpp \
@@ -154,16 +155,17 @@ EXPORTS =  			\
 EXPORTS_NAMESPACES = mozilla/dom
 
 EXPORTS_mozilla/dom = \
 	SVGAElement.h \
 	SVGAltGlyphElement.h \
 	SVGAngle.h \
 	SVGAnimatedAngle.h \
 	SVGAnimatedBoolean.h \
+	SVGAnimatedLength.h \
 	SVGAnimateElement.h \
 	SVGAnimateTransformElement.h \
 	SVGAnimateMotionElement.h \
 	SVGAnimationElement.h \
 	SVGClipPathElement.h \
 	SVGCircleElement.h \
 	SVGDefsElement.h \
 	SVGDescElement.h \

new file mode 100644
--- /dev/null
+++ b/content/svg/content/src/SVGAnimatedLength.cpp
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/SVGAnimatedLength.h"
+#include "mozilla/dom/SVGAnimatedLengthBinding.h"
+
+DOMCI_DATA(SVGAnimatedLength, mozilla::dom::SVGAnimatedLength)
+
+namespace mozilla {
+namespace dom {
+
+NS_SVG_VAL_IMPL_CYCLE_COLLECTION_WRAPPERCACHED(SVGAnimatedLength, mSVGElement)
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(SVGAnimatedLength)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(SVGAnimatedLength)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(SVGAnimatedLength)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsIDOMSVGAnimatedLength)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(SVGAnimatedLength)
+NS_INTERFACE_MAP_END
+
+JSObject*
+SVGAnimatedLength::WrapObject(JSContext* aCx, JSObject* aScope, bool* aTriedToWrap)
+{
+  return SVGAnimatedLengthBinding::Wrap(aCx, aScope, this, aTriedToWrap);
+}
+
+already_AddRefed<nsIDOMSVGLength>
+SVGAnimatedLength::BaseVal()
+{
+  nsRefPtr<nsIDOMSVGLength> angle;
+  mVal->ToDOMBaseVal(getter_AddRefs(angle), mSVGElement);
+  return angle.forget();
+}
+
+already_AddRefed<nsIDOMSVGLength>
+SVGAnimatedLength::AnimVal()
+{
+  nsRefPtr<nsIDOMSVGLength> angle;
+  mVal->ToDOMAnimVal(getter_AddRefs(angle), mSVGElement);
+  return angle.forget();
+}
+
+} // namespace dom
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/content/svg/content/src/SVGAnimatedLength.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_SVGAnimatedLength_h
+#define mozilla_dom_SVGAnimatedLength_h
+
+#include "nsSVGElement.h"
+#include "nsSVGLength2.h"
+
+namespace mozilla {
+namespace dom {
+
+class SVGAnimatedLength MOZ_FINAL : public nsIDOMSVGAnimatedLength,
+                                    public nsWrapperCache
+{
+public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(SVGAnimatedLength)
+
+  SVGAnimatedLength(nsSVGLength2* aVal, nsSVGElement *aSVGElement)
+    : mVal(aVal), mSVGElement(aSVGElement)
+  { SetIsDOMBinding(); }
+
+  ~SVGAnimatedLength();
+
+  NS_IMETHOD GetBaseVal(nsIDOMSVGLength **aBaseVal)
+    { *aBaseVal = BaseVal().get(); return NS_OK; }
+
+  NS_IMETHOD GetAnimVal(nsIDOMSVGLength **aAnimVal)
+    { *aAnimVal = AnimVal().get(); return NS_OK; }
+
+  // WebIDL
+  nsSVGElement* GetParentObject() { return mSVGElement; }
+  virtual JSObject* WrapObject(JSContext* aCx, JSObject* aScope, bool* aTriedToWrap);
+  already_AddRefed<nsIDOMSVGLength> BaseVal();
+  already_AddRefed<nsIDOMSVGLength> AnimVal();
+
+protected:
+  nsSVGLength2* mVal; // kept alive because it belongs to content
+  nsRefPtr<nsSVGElement> mSVGElement;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_SVGAnimatedLength_h

--- a/content/svg/content/src/SVGCircleElement.cpp
+++ b/content/svg/content/src/SVGCircleElement.cpp
@@ -1,16 +1,17 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/dom/SVGCircleElement.h"
 #include "nsGkAtoms.h"
 #include "gfxContext.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "mozilla/dom/SVGCircleElementBinding.h"
 
 DOMCI_NODE_DATA(SVGCircleElement, mozilla::dom::SVGCircleElement)
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(Circle)
 
 namespace mozilla {
 namespace dom {
@@ -60,43 +61,43 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGCircl
 
 /* readonly attribute nsIDOMSVGAnimatedLength cx; */
 NS_IMETHODIMP SVGCircleElement::GetCx(nsIDOMSVGAnimatedLength * *aCx)
 {
   *aCx = Cx().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGCircleElement::Cx()
 {
   return mLengthAttributes[ATTR_CX].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength cy; */
 NS_IMETHODIMP SVGCircleElement::GetCy(nsIDOMSVGAnimatedLength * *aCy)
 {
   *aCy = Cy().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGCircleElement::Cy()
 {
   return mLengthAttributes[ATTR_CY].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength r; */
 NS_IMETHODIMP SVGCircleElement::GetR(nsIDOMSVGAnimatedLength * *aR)
 {
   *aR = R().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGCircleElement::R()
 {
   return mLengthAttributes[ATTR_R].ToDOMAnimatedLength(this);
 }
 
 //----------------------------------------------------------------------
 // nsSVGElement methods
 

--- a/content/svg/content/src/SVGCircleElement.h
+++ b/content/svg/content/src/SVGCircleElement.h
@@ -45,19 +45,19 @@ public:
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> Cx();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Cy();
-  already_AddRefed<nsIDOMSVGAnimatedLength> R();
+  already_AddRefed<SVGAnimatedLength> Cx();
+  already_AddRefed<SVGAnimatedLength> Cy();
+  already_AddRefed<SVGAnimatedLength> R();
 
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
 
   enum { ATTR_CX, ATTR_CY, ATTR_R };
   nsSVGLength2 mLengthAttributes[3];
   static LengthInfo sLengthInfo[3];

--- a/content/svg/content/src/SVGEllipseElement.cpp
+++ b/content/svg/content/src/SVGEllipseElement.cpp
@@ -1,13 +1,14 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "mozilla/dom/SVGEllipseElement.h"
 #include "mozilla/dom/SVGEllipseElementBinding.h"
 #include "gfxContext.h"
 
 DOMCI_NODE_DATA(SVGEllipseElement, mozilla::dom::SVGEllipseElement)
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(Ellipse)
 
@@ -60,56 +61,56 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGEllip
 
 /* readonly attribute nsIDOMSVGAnimatedLength cx; */
 NS_IMETHODIMP SVGEllipseElement::GetCx(nsIDOMSVGAnimatedLength * *aCx)
 {
   *aCx = Cx().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGEllipseElement::Cx()
 {
   return mLengthAttributes[CX].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength cy; */
 NS_IMETHODIMP SVGEllipseElement::GetCy(nsIDOMSVGAnimatedLength * *aCy)
 {
   *aCy = Cy().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGEllipseElement::Cy()
 {
   return mLengthAttributes[CY].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength rx; */
 NS_IMETHODIMP SVGEllipseElement::GetRx(nsIDOMSVGAnimatedLength * *aRx)
 {
   *aRx = Rx().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGEllipseElement::Rx()
 {
   return mLengthAttributes[RX].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength ry; */
 NS_IMETHODIMP SVGEllipseElement::GetRy(nsIDOMSVGAnimatedLength * *aRy)
 {
   *aRy = Ry().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGEllipseElement::Ry()
 {
   return mLengthAttributes[RY].ToDOMAnimatedLength(this);
 }
 
 //----------------------------------------------------------------------
 // nsSVGElement methods
 

--- a/content/svg/content/src/SVGEllipseElement.h
+++ b/content/svg/content/src/SVGEllipseElement.h
@@ -45,20 +45,20 @@ public:
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> Cx();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Cy();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Rx();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Ry();
+  already_AddRefed<SVGAnimatedLength> Cx();
+  already_AddRefed<SVGAnimatedLength> Cy();
+  already_AddRefed<SVGAnimatedLength> Rx();
+  already_AddRefed<SVGAnimatedLength> Ry();
 
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
 
   enum { CX, CY, RX, RY };
   nsSVGLength2 mLengthAttributes[4];
   static LengthInfo sLengthInfo[4];

--- a/content/svg/content/src/SVGForeignObjectElement.cpp
+++ b/content/svg/content/src/SVGForeignObjectElement.cpp
@@ -1,16 +1,17 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/Util.h"
 
 #include "nsCOMPtr.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "mozilla/dom/SVGForeignObjectElement.h"
 #include "mozilla/dom/SVGForeignObjectElementBinding.h"
 
 DOMCI_NODE_DATA(SVGForeignObjectElement, mozilla::dom::SVGForeignObjectElement)
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(ForeignObject)
 
 namespace mozilla {
@@ -62,58 +63,58 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGForei
 
 /* readonly attribute nsIDOMSVGAnimatedLength x; */
 NS_IMETHODIMP SVGForeignObjectElement::GetX(nsIDOMSVGAnimatedLength * *aX)
 {
   *aX = X().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGForeignObjectElement::X()
 {
   return mLengthAttributes[ATTR_X].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y; */
 NS_IMETHODIMP SVGForeignObjectElement::GetY(nsIDOMSVGAnimatedLength * *aY)
 {
   *aY = Y().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGForeignObjectElement::Y()
 {
   return mLengthAttributes[ATTR_Y].ToDOMAnimatedLength(this);
 }
 
 
 /* readonly attribute nsIDOMSVGAnimatedLength width; */
 NS_IMETHODIMP SVGForeignObjectElement::GetWidth(nsIDOMSVGAnimatedLength * *aWidth)
 {
   *aWidth = Width().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGForeignObjectElement::Width()
 {
   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 }
 
 
 /* readonly attribute nsIDOMSVGAnimatedLength height; */
 NS_IMETHODIMP SVGForeignObjectElement::GetHeight(nsIDOMSVGAnimatedLength * *aHeight)
 {
   *aHeight = Height().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGForeignObjectElement::Height()
 {
   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 }
 
 //----------------------------------------------------------------------
 // nsSVGElement methods
 

--- a/content/svg/content/src/SVGForeignObjectElement.h
+++ b/content/svg/content/src/SVGForeignObjectElement.h
@@ -50,20 +50,20 @@ public:
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> X();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Width();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Height();
+  already_AddRefed<SVGAnimatedLength> X();
+  already_AddRefed<SVGAnimatedLength> Y();
+  already_AddRefed<SVGAnimatedLength> Width();
+  already_AddRefed<SVGAnimatedLength> Height();
 
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
 
   enum { ATTR_X, ATTR_Y, ATTR_WIDTH, ATTR_HEIGHT };
   nsSVGLength2 mLengthAttributes[4];
   static LengthInfo sLengthInfo[4];

--- a/content/svg/content/src/SVGGradientElement.cpp
+++ b/content/svg/content/src/SVGGradientElement.cpp
@@ -1,16 +1,17 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/dom/SVGGradientElement.h"
 
 #include "DOMSVGAnimatedTransformList.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "mozilla/dom/SVGRadialGradientElementBinding.h"
 #include "mozilla/dom/SVGLinearGradientElementBinding.h"
 #include "mozilla/Util.h"
 #include "nsCOMPtr.h"
 #include "nsGkAtoms.h"
 #include "nsIDOMMutationEvent.h"
 #include "nsIDOMSVGAnimatedEnum.h"
 #include "nsIDOMSVGGradientElement.h"
@@ -217,56 +218,56 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGLinea
 
 /* readonly attribute nsIDOMSVGAnimatedLength x1; */
 NS_IMETHODIMP SVGLinearGradientElement::GetX1(nsIDOMSVGAnimatedLength * *aX1)
 {
   *aX1 = X1().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLinearGradientElement::X1()
 {
   return mLengthAttributes[ATTR_X1].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y1; */
 NS_IMETHODIMP SVGLinearGradientElement::GetY1(nsIDOMSVGAnimatedLength * *aY1)
 {
   *aY1 = Y1().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLinearGradientElement::Y1()
 {
   return mLengthAttributes[ATTR_Y1].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength x2; */
 NS_IMETHODIMP SVGLinearGradientElement::GetX2(nsIDOMSVGAnimatedLength * *aX2)
 {
   *aX2 = X2().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLinearGradientElement::X2()
 {
   return mLengthAttributes[ATTR_X2].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y2; */
 NS_IMETHODIMP SVGLinearGradientElement::GetY2(nsIDOMSVGAnimatedLength * *aY2)
 {
   *aY2 = Y2().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLinearGradientElement::Y2()
 {
   return mLengthAttributes[ATTR_Y2].ToDOMAnimatedLength(this);
 }
 
 
 //----------------------------------------------------------------------
 // nsSVGElement methods
@@ -337,69 +338,69 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGRadia
 
 /* readonly attribute nsIDOMSVGAnimatedLength cx; */
 NS_IMETHODIMP SVGRadialGradientElement::GetCx(nsIDOMSVGAnimatedLength * *aCx)
 {
   *aCx = Cx().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRadialGradientElement::Cx()
 {
   return mLengthAttributes[ATTR_CX].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength cy; */
 NS_IMETHODIMP SVGRadialGradientElement::GetCy(nsIDOMSVGAnimatedLength * *aCy)
 {
   *aCy = Cy().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRadialGradientElement::Cy()
 {
   return mLengthAttributes[ATTR_CY].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength r; */
 NS_IMETHODIMP SVGRadialGradientElement::GetR(nsIDOMSVGAnimatedLength * *aR)
 {
   *aR = R().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRadialGradientElement::R()
 {
   return mLengthAttributes[ATTR_R].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength fx; */
 NS_IMETHODIMP SVGRadialGradientElement::GetFx(nsIDOMSVGAnimatedLength * *aFx)
 {
   *aFx = Fx().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRadialGradientElement::Fx()
 {
   return mLengthAttributes[ATTR_FX].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength fy; */
 NS_IMETHODIMP SVGRadialGradientElement::GetFy(nsIDOMSVGAnimatedLength * *aFy)
 {
   *aFy = Fy().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRadialGradientElement::Fy()
 {
   return mLengthAttributes[ATTR_FY].ToDOMAnimatedLength(this);
 }
 
 //----------------------------------------------------------------------
 // nsSVGElement methods
 

--- a/content/svg/content/src/SVGGradientElement.h
+++ b/content/svg/content/src/SVGGradientElement.h
@@ -124,20 +124,20 @@ public:
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> X1();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y1();
-  already_AddRefed<nsIDOMSVGAnimatedLength> X2();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y2();
+  already_AddRefed<SVGAnimatedLength> X1();
+  already_AddRefed<SVGAnimatedLength> Y1();
+  already_AddRefed<SVGAnimatedLength> X2();
+  already_AddRefed<SVGAnimatedLength> Y2();
 
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
 
   // nsIDOMSVGLinearGradientElement values
   enum { ATTR_X1, ATTR_Y1, ATTR_X2, ATTR_Y2 };
   nsSVGLength2 mLengthAttributes[4];
@@ -179,21 +179,21 @@ public:
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> Cx();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Cy();
-  already_AddRefed<nsIDOMSVGAnimatedLength> R();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Fx();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Fy();
+  already_AddRefed<SVGAnimatedLength> Cx();
+  already_AddRefed<SVGAnimatedLength> Cy();
+  already_AddRefed<SVGAnimatedLength> R();
+  already_AddRefed<SVGAnimatedLength> Fx();
+  already_AddRefed<SVGAnimatedLength> Fy();
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
 
   // nsIDOMSVGRadialGradientElement values
   enum { ATTR_CX, ATTR_CY, ATTR_R, ATTR_FX, ATTR_FY };
   nsSVGLength2 mLengthAttributes[5];
   static LengthInfo sLengthInfo[5];

--- a/content/svg/content/src/SVGImageElement.cpp
+++ b/content/svg/content/src/SVGImageElement.cpp
@@ -1,16 +1,17 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/Util.h"
 
 #include "mozilla/dom/SVGImageElement.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "nsCOMPtr.h"
 #include "nsIURI.h"
 #include "nsNetUtil.h"
 #include "imgIContainer.h"
 #include "imgINotificationObserver.h"
 #include "gfxContext.h"
 #include "mozilla/dom/SVGImageElementBinding.h"
 
@@ -83,56 +84,56 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGImage
 
 /* readonly attribute nsIDOMSVGAnimatedLength x; */
 NS_IMETHODIMP SVGImageElement::GetX(nsIDOMSVGAnimatedLength * *aX)
 {
   *aX = X().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGImageElement::X()
 {
   return mLengthAttributes[ATTR_X].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y; */
 NS_IMETHODIMP SVGImageElement::GetY(nsIDOMSVGAnimatedLength * *aY)
 {
   *aY = Y().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGImageElement::Y()
 {
   return mLengthAttributes[ATTR_Y].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength width; */
 NS_IMETHODIMP SVGImageElement::GetWidth(nsIDOMSVGAnimatedLength * *aWidth)
 {
   *aWidth = Width().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGImageElement::Width()
 {
   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength height; */
 NS_IMETHODIMP SVGImageElement::GetHeight(nsIDOMSVGAnimatedLength * *aHeight)
 {
   *aHeight = Height().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGImageElement::Height()
 {
   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute SVGPreserveAspectRatio preserveAspectRatio; */
 NS_IMETHODIMP
 SVGImageElement::GetPreserveAspectRatio(nsISupports

--- a/content/svg/content/src/SVGImageElement.h
+++ b/content/svg/content/src/SVGImageElement.h
@@ -77,20 +77,20 @@ public:
 
   bool IsImageSrcSetDisabled() const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> X();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Width();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Height();
+  already_AddRefed<SVGAnimatedLength> X();
+  already_AddRefed<SVGAnimatedLength> Y();
+  already_AddRefed<SVGAnimatedLength> Width();
+  already_AddRefed<SVGAnimatedLength> Height();
   already_AddRefed<DOMSVGAnimatedPreserveAspectRatio> PreserveAspectRatio();
   already_AddRefed<nsIDOMSVGAnimatedString> Href();
 
 protected:
   nsresult LoadSVGImage(bool aForce, bool aNotify);
 
   virtual LengthAttributesInfo GetLengthInfo();
   virtual SVGAnimatedPreserveAspectRatio *GetPreserveAspectRatio();

--- a/content/svg/content/src/SVGLineElement.cpp
+++ b/content/svg/content/src/SVGLineElement.cpp
@@ -1,13 +1,14 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "mozilla/dom/SVGLineElement.h"
 #include "mozilla/dom/SVGLineElementBinding.h"
 #include "gfxContext.h"
 
 DOMCI_NODE_DATA(SVGLineElement, mozilla::dom::SVGLineElement)
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(Line)
 
@@ -60,56 +61,56 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGLineE
 
 /* readonly attribute nsIDOMSVGAnimatedLength cx; */
 NS_IMETHODIMP SVGLineElement::GetX1(nsIDOMSVGAnimatedLength * *aX1)
 {
   *aX1 = X1().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLineElement::X1()
 {
   return mLengthAttributes[ATTR_X1].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength cy; */
 NS_IMETHODIMP SVGLineElement::GetY1(nsIDOMSVGAnimatedLength * *aY1)
 {
   *aY1 = Y1().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLineElement::Y1()
 {
   return mLengthAttributes[ATTR_Y1].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength rx; */
 NS_IMETHODIMP SVGLineElement::GetX2(nsIDOMSVGAnimatedLength * *aX2)
 {
   *aX2 = X2().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLineElement::X2()
 {
   return mLengthAttributes[ATTR_X2].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength ry; */
 NS_IMETHODIMP SVGLineElement::GetY2(nsIDOMSVGAnimatedLength * *aY2)
 {
   *aY2 = Y2().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGLineElement::Y2()
 {
   return mLengthAttributes[ATTR_Y2].ToDOMAnimatedLength(this);
 }
 
 
 //----------------------------------------------------------------------
 // nsIContent methods

--- a/content/svg/content/src/SVGLineElement.h
+++ b/content/svg/content/src/SVGLineElement.h
@@ -47,20 +47,20 @@ public:
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> X1();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y1();
-  already_AddRefed<nsIDOMSVGAnimatedLength> X2();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y2();
+  already_AddRefed<SVGAnimatedLength> X1();
+  already_AddRefed<SVGAnimatedLength> Y1();
+  already_AddRefed<SVGAnimatedLength> X2();
+  already_AddRefed<SVGAnimatedLength> Y2();
 
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
 
   enum { ATTR_X1, ATTR_Y1, ATTR_X2, ATTR_Y2 };
   nsSVGLength2 mLengthAttributes[4];
   static LengthInfo sLengthInfo[4];

--- a/content/svg/content/src/SVGPatternElement.cpp
+++ b/content/svg/content/src/SVGPatternElement.cpp
@@ -4,16 +4,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/Util.h"
 
 #include "DOMSVGAnimatedTransformList.h"
 #include "nsIDOMMutationEvent.h"
 #include "nsCOMPtr.h"
 #include "nsGkAtoms.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "mozilla/dom/SVGPatternElement.h"
 #include "mozilla/dom/SVGPatternElementBinding.h"
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(Pattern)
 
 DOMCI_NODE_DATA(SVGPatternElement, mozilla::dom::SVGPatternElement)
 
 namespace mozilla {
@@ -161,56 +162,56 @@ SVGPatternElement::PatternTransform()
 
 /* readonly attribute nsIDOMSVGAnimatedLength x; */
 NS_IMETHODIMP SVGPatternElement::GetX(nsIDOMSVGAnimatedLength * *aX)
 {
   *aX = X().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGPatternElement::X()
 {
   return mLengthAttributes[ATTR_X].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y; */
 NS_IMETHODIMP SVGPatternElement::GetY(nsIDOMSVGAnimatedLength * *aY)
 {
   *aY = Y().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGPatternElement::Y()
 {
   return mLengthAttributes[ATTR_Y].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength width; */
 NS_IMETHODIMP SVGPatternElement::GetWidth(nsIDOMSVGAnimatedLength * *aWidth)
 {
   *aWidth = Width().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGPatternElement::Width()
 {
   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength height; */
 NS_IMETHODIMP SVGPatternElement::GetHeight(nsIDOMSVGAnimatedLength * *aHeight)
 {
   *aHeight = Height().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGPatternElement::Height()
 {
   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 }
 
 //----------------------------------------------------------------------
 // nsIDOMSVGURIReference methods:
 

--- a/content/svg/content/src/SVGPatternElement.h
+++ b/content/svg/content/src/SVGPatternElement.h
@@ -82,20 +82,20 @@ public:
   }
 
   // WebIDL
   already_AddRefed<nsIDOMSVGAnimatedRect> ViewBox();
   already_AddRefed<DOMSVGAnimatedPreserveAspectRatio> PreserveAspectRatio();
   already_AddRefed<nsIDOMSVGAnimatedEnumeration> PatternUnits();
   already_AddRefed<nsIDOMSVGAnimatedEnumeration> PatternContentUnits();
   already_AddRefed<DOMSVGAnimatedTransformList> PatternTransform();
-  already_AddRefed<nsIDOMSVGAnimatedLength> X();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Width();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Height();
+  already_AddRefed<SVGAnimatedLength> X();
+  already_AddRefed<SVGAnimatedLength> Y();
+  already_AddRefed<SVGAnimatedLength> Width();
+  already_AddRefed<SVGAnimatedLength> Height();
   already_AddRefed<nsIDOMSVGAnimatedString> Href();
 
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
   virtual EnumAttributesInfo GetEnumInfo();
   virtual nsSVGViewBox *GetViewBox();
   virtual SVGAnimatedPreserveAspectRatio *GetPreserveAspectRatio();

--- a/content/svg/content/src/SVGRectElement.cpp
+++ b/content/svg/content/src/SVGRectElement.cpp
@@ -2,16 +2,17 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/dom/SVGRectElement.h"
 #include "nsGkAtoms.h"
 #include "gfxContext.h"
 #include "mozilla/dom/SVGRectElementBinding.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include <algorithm>
 
 DOMCI_NODE_DATA(SVGRectElement, mozilla::dom::SVGRectElement)
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(Rect)
 
 namespace mozilla {
 namespace dom {
@@ -64,82 +65,82 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGRectE
 
 /* readonly attribute nsIDOMSVGAnimatedLength x; */
 NS_IMETHODIMP SVGRectElement::GetX(nsIDOMSVGAnimatedLength * *aX)
 {
   *aX = X().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRectElement::X()
 {
   return mLengthAttributes[ATTR_X].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y; */
 NS_IMETHODIMP SVGRectElement::GetY(nsIDOMSVGAnimatedLength * *aY)
 {
   *aY = Y().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRectElement::Y()
 {
   return mLengthAttributes[ATTR_Y].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength width; */
 NS_IMETHODIMP SVGRectElement::GetWidth(nsIDOMSVGAnimatedLength * *aWidth)
 {
   *aWidth = Width().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRectElement::Width()
 {
   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength height; */
 NS_IMETHODIMP SVGRectElement::GetHeight(nsIDOMSVGAnimatedLength * *aHeight)
 {
   *aHeight = Height().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRectElement::Height()
 {
   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength rx; */
 NS_IMETHODIMP SVGRectElement::GetRx(nsIDOMSVGAnimatedLength * *aRx)
 {
   *aRx = Rx().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRectElement::Rx()
 {
   return mLengthAttributes[ATTR_RX].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength ry; */
 NS_IMETHODIMP SVGRectElement::GetRy(nsIDOMSVGAnimatedLength * *aRy)
 {
   *aRy = Ry().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGRectElement::Ry()
 {
   return mLengthAttributes[ATTR_RY].ToDOMAnimatedLength(this);
 }
 
 //----------------------------------------------------------------------
 // nsSVGElement methods
 

--- a/content/svg/content/src/SVGRectElement.h
+++ b/content/svg/content/src/SVGRectElement.h
@@ -45,22 +45,22 @@ public:
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> X();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Height();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Width();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Rx();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Ry();
+  already_AddRefed<SVGAnimatedLength> X();
+  already_AddRefed<SVGAnimatedLength> Y();
+  already_AddRefed<SVGAnimatedLength> Height();
+  already_AddRefed<SVGAnimatedLength> Width();
+  already_AddRefed<SVGAnimatedLength> Rx();
+  already_AddRefed<SVGAnimatedLength> Ry();
 
 protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
 
   enum { ATTR_X, ATTR_Y, ATTR_WIDTH, ATTR_HEIGHT, ATTR_RX, ATTR_RY };
   nsSVGLength2 mLengthAttributes[6];
   static LengthInfo sLengthInfo[6];

--- a/content/svg/content/src/SVGSVGElement.cpp
+++ b/content/svg/content/src/SVGSVGElement.cpp
@@ -34,16 +34,17 @@
 #include "SVGContentUtils.h"
 
 #include "nsEventDispatcher.h"
 #include "nsSMILTimeContainer.h"
 #include "nsSMILAnimationController.h"
 #include "nsSMILTypes.h"
 #include "nsIContentIterator.h"
 #include "SVGAngle.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include <algorithm>
 
 DOMCI_NODE_DATA(SVGSVGElement, mozilla::dom::SVGSVGElement)
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT_CHECK_PARSER(SVG)
 
 namespace mozilla {
 namespace dom {
@@ -203,59 +204,59 @@ SVGSVGElement::Clone(nsINodeInfo *aNodeI
 /* readonly attribute nsIDOMSVGAnimatedLength x; */
 NS_IMETHODIMP
 SVGSVGElement::GetX(nsIDOMSVGAnimatedLength * *aX)
 {
   *aX = X().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGSVGElement::X()
 {
   return mLengthAttributes[ATTR_X].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y; */
 NS_IMETHODIMP
 SVGSVGElement::GetY(nsIDOMSVGAnimatedLength * *aY)
 {
   *aY = Y().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGSVGElement::Y()
 {
   return mLengthAttributes[ATTR_Y].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength width; */
 NS_IMETHODIMP
 SVGSVGElement::GetWidth(nsIDOMSVGAnimatedLength * *aWidth)
 {
   *aWidth = Width().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGSVGElement::Width()
 {
   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength height; */
 NS_IMETHODIMP
 SVGSVGElement::GetHeight(nsIDOMSVGAnimatedLength * *aHeight)
 {
   *aHeight = Height().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGSVGElement::Height()
 {
   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute float pixelUnitToMillimeterX; */
 NS_IMETHODIMP
 SVGSVGElement::GetPixelUnitToMillimeterX(float *aPixelUnitToMillimeterX)

--- a/content/svg/content/src/SVGSVGElement.h
+++ b/content/svg/content/src/SVGSVGElement.h
@@ -226,20 +226,20 @@ public:
     mViewportHeight = aSize.height;
   }
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> X();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Width();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Height();
+  already_AddRefed<SVGAnimatedLength> X();
+  already_AddRefed<SVGAnimatedLength> Y();
+  already_AddRefed<SVGAnimatedLength> Width();
+  already_AddRefed<SVGAnimatedLength> Height();
   float PixelUnitToMillimeterX();
   float PixelUnitToMillimeterY();
   float ScreenPixelToMillimeterX();
   float ScreenPixelToMillimeterY();
   bool UseCurrentView();
   // XPIDL SetCurrentScale and SetCurrentTranslate are alright to use because
   // they only throw on non-finite floats and we don't allow those.
   float CurrentScale();

--- a/content/svg/content/src/SVGTextPathElement.cpp
+++ b/content/svg/content/src/SVGTextPathElement.cpp
@@ -7,16 +7,17 @@
 #include "mozilla/dom/SVGTextPathElementBinding.h"
 #include "nsSVGElement.h"
 #include "nsGkAtoms.h"
 #include "nsIDOMSVGTextPathElement.h"
 #include "nsIDOMSVGURIReference.h"
 #include "nsIFrame.h"
 #include "nsError.h"
 #include "nsContentUtils.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 
 DOMCI_NODE_DATA(SVGTextPathElement, mozilla::dom::SVGTextPathElement)
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(TextPath)
 
 namespace mozilla {
 namespace dom {
 
@@ -110,17 +111,17 @@ SVGTextPathElement::Href()
 // nsIDOMSVGTextPathElement methods
 
 NS_IMETHODIMP SVGTextPathElement::GetStartOffset(nsIDOMSVGAnimatedLength * *aStartOffset)
 {
   *aStartOffset = StartOffset().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGTextPathElement::StartOffset()
 {
   return mLengthAttributes[STARTOFFSET].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedEnumeration method; */
 NS_IMETHODIMP SVGTextPathElement::GetMethod(nsIDOMSVGAnimatedEnumeration * *aMethod)
 {

--- a/content/svg/content/src/SVGTextPathElement.h
+++ b/content/svg/content/src/SVGTextPathElement.h
@@ -67,17 +67,17 @@ public:
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   virtual bool IsEventAttributeName(nsIAtom* aName) MOZ_OVERRIDE;
 
   // WebIDL
-  already_AddRefed<nsIDOMSVGAnimatedLength> StartOffset();
+  already_AddRefed<SVGAnimatedLength> StartOffset();
   already_AddRefed<nsIDOMSVGAnimatedEnumeration> Method();
   already_AddRefed<nsIDOMSVGAnimatedEnumeration> Spacing();
   already_AddRefed<nsIDOMSVGAnimatedString> Href();
 
  protected:
 
   virtual LengthAttributesInfo GetLengthInfo();
   virtual EnumAttributesInfo GetEnumInfo();

--- a/content/svg/content/src/SVGUseElement.cpp
+++ b/content/svg/content/src/SVGUseElement.cpp
@@ -1,15 +1,16 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/Util.h"
 
+#include "mozilla/dom/SVGAnimatedLength.h"
 #include "mozilla/dom/SVGUseElement.h"
 #include "mozilla/dom/SVGUseElementBinding.h"
 #include "nsIDOMSVGGElement.h"
 #include "nsGkAtoms.h"
 #include "mozilla/dom/SVGSVGElement.h"
 #include "nsIDOMSVGSymbolElement.h"
 #include "nsIDocument.h"
 #include "nsIPresShell.h"
@@ -150,56 +151,56 @@ SVGUseElement::Href()
 
 /* readonly attribute nsIDOMSVGAnimatedLength x; */
 NS_IMETHODIMP SVGUseElement::GetX(nsIDOMSVGAnimatedLength * *aX)
 {
   *aX = X().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGUseElement::X()
 {
   return mLengthAttributes[ATTR_X].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength y; */
 NS_IMETHODIMP SVGUseElement::GetY(nsIDOMSVGAnimatedLength * *aY)
 {
   *aY = Y().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGUseElement::Y()
 {
   return mLengthAttributes[ATTR_Y].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength width; */
 NS_IMETHODIMP SVGUseElement::GetWidth(nsIDOMSVGAnimatedLength * *aWidth)
 {
   *aWidth = Width().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGUseElement::Width()
 {
   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 }
 
 /* readonly attribute nsIDOMSVGAnimatedLength height; */
 NS_IMETHODIMP SVGUseElement::GetHeight(nsIDOMSVGAnimatedLength * *aHeight)
 {
   *aHeight = Height().get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 SVGUseElement::Height()
 {
   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 }
 
 //----------------------------------------------------------------------
 // nsIMutationObserver methods
 

--- a/content/svg/content/src/SVGUseElement.h
+++ b/content/svg/content/src/SVGUseElement.h
@@ -86,20 +86,20 @@ public:
   NS_IMETHOD_(bool) IsAttributeMapped(const nsIAtom* aAttribute) const;
 
   virtual nsXPCClassInfo* GetClassInfo();
 
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
   // WebIDL
   already_AddRefed<nsIDOMSVGAnimatedString> Href();
-  already_AddRefed<nsIDOMSVGAnimatedLength> X();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Y();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Width();
-  already_AddRefed<nsIDOMSVGAnimatedLength> Height();
+  already_AddRefed<SVGAnimatedLength> X();
+  already_AddRefed<SVGAnimatedLength> Y();
+  already_AddRefed<SVGAnimatedLength> Width();
+  already_AddRefed<SVGAnimatedLength> Height();
 
 protected:
   class SourceReference : public nsReferencedElement {
   public:
     SourceReference(SVGUseElement* aContainer) : mContainer(aContainer) {}
   protected:
     virtual void ElementChanged(Element* aFrom, Element* aTo) {
       nsReferencedElement::ElementChanged(aFrom, aTo);

--- a/content/svg/content/src/nsSVGLength2.cpp
+++ b/content/svg/content/src/nsSVGLength2.cpp
@@ -11,71 +11,59 @@
 #include "mozilla/dom/SVGSVGElement.h"
 #include "nsIFrame.h"
 #include "nsSVGIntegrationUtils.h"
 #include "nsSVGAttrTearoffTable.h"
 #include "nsContentUtils.h" // NS_ENSURE_FINITE
 #include "nsSMILValue.h"
 #include "nsSMILFloatType.h"
 #include "nsAttrValueInlines.h"
+#include "mozilla/dom/SVGAnimatedLength.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 NS_SVG_VAL_IMPL_CYCLE_COLLECTION(nsSVGLength2::DOMBaseVal, mSVGElement)
 
 NS_SVG_VAL_IMPL_CYCLE_COLLECTION(nsSVGLength2::DOMAnimVal, mSVGElement)
 
-NS_SVG_VAL_IMPL_CYCLE_COLLECTION(nsSVGLength2::DOMAnimatedLength, mSVGElement)
-
 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsSVGLength2::DOMBaseVal)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsSVGLength2::DOMBaseVal)
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsSVGLength2::DOMAnimVal)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsSVGLength2::DOMAnimVal)
 
-NS_IMPL_CYCLE_COLLECTING_ADDREF(nsSVGLength2::DOMAnimatedLength)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(nsSVGLength2::DOMAnimatedLength)
-
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsSVGLength2::DOMBaseVal)
   NS_INTERFACE_MAP_ENTRY(nsIDOMSVGLength)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(SVGLength)
 NS_INTERFACE_MAP_END
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsSVGLength2::DOMAnimVal)
   NS_INTERFACE_MAP_ENTRY(nsIDOMSVGLength)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(SVGLength)
 NS_INTERFACE_MAP_END
 
-DOMCI_DATA(SVGAnimatedLength, nsSVGLength2::DOMAnimatedLength)
-
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsSVGLength2::DOMAnimatedLength)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMSVGAnimatedLength)
-  NS_INTERFACE_MAP_ENTRY(nsISupports)
-  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(SVGAnimatedLength)
-NS_INTERFACE_MAP_END
-
 static nsIAtom** const unitMap[] =
 {
   nullptr, /* SVG_LENGTHTYPE_UNKNOWN */
   nullptr, /* SVG_LENGTHTYPE_NUMBER */
   &nsGkAtoms::percentage,
   &nsGkAtoms::em,
   &nsGkAtoms::ex,
   &nsGkAtoms::px,
   &nsGkAtoms::cm,
   &nsGkAtoms::mm,
   &nsGkAtoms::in,
   &nsGkAtoms::pt,
   &nsGkAtoms::pc
 };
 
-static nsSVGAttrTearoffTable<nsSVGLength2, nsSVGLength2::DOMAnimatedLength>
+static nsSVGAttrTearoffTable<nsSVGLength2, SVGAnimatedLength>
   sSVGAnimatedLengthTearoffTable;
 static nsSVGAttrTearoffTable<nsSVGLength2, nsSVGLength2::DOMBaseVal>
   sBaseSVGLengthTearoffTable;
 static nsSVGAttrTearoffTable<nsSVGLength2, nsSVGLength2::DOMAnimVal>
   sAnimSVGLengthTearoffTable;
 
 /* Helper functions */
 
@@ -486,30 +474,30 @@ nsSVGLength2::SetAnimValue(float aValue,
 nsresult
 nsSVGLength2::ToDOMAnimatedLength(nsIDOMSVGAnimatedLength **aResult,
                                   nsSVGElement *aSVGElement)
 {
   *aResult = ToDOMAnimatedLength(aSVGElement).get();
   return NS_OK;
 }
 
-already_AddRefed<nsIDOMSVGAnimatedLength>
+already_AddRefed<SVGAnimatedLength>
 nsSVGLength2::ToDOMAnimatedLength(nsSVGElement* aSVGElement)
 {
-  nsRefPtr<DOMAnimatedLength> domAnimatedLength =
+  nsRefPtr<SVGAnimatedLength> svgAnimatedLength =
     sSVGAnimatedLengthTearoffTable.GetTearoff(this);
-  if (!domAnimatedLength) {
-    domAnimatedLength = new DOMAnimatedLength(this, aSVGElement);
-    sSVGAnimatedLengthTearoffTable.AddTearoff(this, domAnimatedLength);
+  if (!svgAnimatedLength) {
+    svgAnimatedLength = new SVGAnimatedLength(this, aSVGElement);
+    sSVGAnimatedLengthTearoffTable.AddTearoff(this, svgAnimatedLength);
   }
 
-  return domAnimatedLength.forget();
+  return svgAnimatedLength.forget();
 }
 
-nsSVGLength2::DOMAnimatedLength::~DOMAnimatedLength()
+SVGAnimatedLength::~SVGAnimatedLength()
 {
   sSVGAnimatedLengthTearoffTable.RemoveTearoff(mVal);
 }
 
 nsISMILAttr*
 nsSVGLength2::ToSMILAttr(nsSVGElement *aSVGElement)
 {
   return new SMILLength(this, aSVGElement);

--- a/content/svg/content/src/nsSVGLength2.h
+++ b/content/svg/content/src/nsSVGLength2.h
@@ -18,23 +18,24 @@
 #include "SVGContentUtils.h"
 
 class nsIFrame;
 class nsISMILAnimationElement;
 class nsSMILValue;
 
 namespace mozilla {
 namespace dom {
+class SVGAnimatedLength;
 class SVGSVGElement;
 }
 }
 
 class nsSVGLength2
 {
-
+  friend class mozilla::dom::SVGAnimatedLength;
 public:
   void Init(uint8_t aCtxType = SVGContentUtils::XY,
             uint8_t aAttrEnum = 0xff,
             float aValue = 0,
             uint8_t aUnitType = nsIDOMSVGLength::SVG_LENGTHTYPE_NUMBER) {
     mAnimVal = mBaseVal = aValue;
     mSpecifiedUnitType = aUnitType;
     mAttrEnum = aAttrEnum;
@@ -86,17 +87,17 @@ public:
   // If this returns false, the animated value is still valid, that is,
   // useable, and represents the default base value of the attribute.
   bool IsExplicitlySet() const
     { return mIsAnimated || mIsBaseSet; }
   
   nsresult ToDOMAnimatedLength(nsIDOMSVGAnimatedLength **aResult,
                                nsSVGElement* aSVGElement);
 
-  already_AddRefed<nsIDOMSVGAnimatedLength>
+  already_AddRefed<mozilla::dom::SVGAnimatedLength>
   ToDOMAnimatedLength(nsSVGElement* aSVGElement);
 
   // Returns a new nsISMILAttr object that the caller must delete
   nsISMILAttr* ToSMILAttr(nsSVGElement* aSVGElement);
 
 private:
   
   float mAnimVal;
@@ -240,35 +241,16 @@ public:
     NS_IMETHOD NewValueSpecifiedUnits(uint16_t unitType,
                                       float valueInSpecifiedUnits)
       { return NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR; }
 
     NS_IMETHOD ConvertToSpecifiedUnits(uint16_t unitType)
       { return NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR; }
   };
 
-  struct DOMAnimatedLength : public nsIDOMSVGAnimatedLength
-  {
-    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-    NS_DECL_CYCLE_COLLECTION_CLASS(DOMAnimatedLength)
-
-    DOMAnimatedLength(nsSVGLength2* aVal, nsSVGElement *aSVGElement)
-      : mVal(aVal), mSVGElement(aSVGElement) {}
-    virtual ~DOMAnimatedLength();
-    
-    nsSVGLength2* mVal; // kept alive because it belongs to content
-    nsRefPtr<nsSVGElement> mSVGElement;
-
-    NS_IMETHOD GetBaseVal(nsIDOMSVGLength **aBaseVal)
-      { return mVal->ToDOMBaseVal(aBaseVal, mSVGElement); }
-
-    NS_IMETHOD GetAnimVal(nsIDOMSVGLength **aAnimVal)
-      { return mVal->ToDOMAnimVal(aAnimVal, mSVGElement); }
-  };
-
   struct SMILLength : public nsISMILAttr
   {
   public:
     SMILLength(nsSVGLength2* aVal, nsSVGElement *aSVGElement)
       : mVal(aVal), mSVGElement(aSVGElement) {}
 
     // These will stay alive because a nsISMILAttr only lives as long
     // as the Compositing step, and DOM elements don't get a chance to

new file mode 100644
--- /dev/null
+++ b/dom/webidl/SVGAnimatedLength.webidl
@@ -0,0 +1,21 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * http://www.w3.org/TR/SVG2/
+ *
+ * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
+ * liability, trademark and document use rules apply.
+ */
+
+interface SVGLength;
+
+interface SVGAnimatedLength {
+  [Constant]
+  readonly attribute SVGLength baseVal;
+  [Constant]
+  readonly attribute SVGLength animVal;
+};
+

--- a/dom/webidl/SVGCircleElement.webidl
+++ b/dom/webidl/SVGCircleElement.webidl
@@ -5,18 +5,16 @@
  *
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
-interface SVGAnimatedLength;
-
 interface SVGCircleElement : SVGGraphicsElement {
   [Constant]
   readonly attribute SVGAnimatedLength cx;
   [Constant]
   readonly attribute SVGAnimatedLength cy;
   [Constant]
   readonly attribute SVGAnimatedLength r;
 };

--- a/dom/webidl/SVGEllipseElement.webidl
+++ b/dom/webidl/SVGEllipseElement.webidl
@@ -5,18 +5,16 @@
  *
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
-interface SVGAnimatedLength;
-
 interface SVGEllipseElement : SVGGraphicsElement {
   [Constant]
   readonly attribute SVGAnimatedLength cx;
   [Constant]
   readonly attribute SVGAnimatedLength cy;
   [Constant]
   readonly attribute SVGAnimatedLength rx;
   [Constant]

--- a/dom/webidl/SVGForeignObjectElement.webidl
+++ b/dom/webidl/SVGForeignObjectElement.webidl
@@ -5,18 +5,16 @@
  *
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
-interface SVGAnimatedLength;
-
 interface SVGForeignObjectElement : SVGGraphicsElement {
   [Constant]
   readonly attribute SVGAnimatedLength x;
   [Constant]
   readonly attribute SVGAnimatedLength y;
   [Constant]
   readonly attribute SVGAnimatedLength width;
   [Constant]

--- a/dom/webidl/SVGLineElement.webidl
+++ b/dom/webidl/SVGLineElement.webidl
@@ -5,18 +5,16 @@
  *
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
-interface SVGAnimatedLength;
-
 interface SVGLineElement : SVGGraphicsElement {
   [Constant]
   readonly attribute SVGAnimatedLength x1;
   [Constant]
   readonly attribute SVGAnimatedLength y1;
   [Constant]
   readonly attribute SVGAnimatedLength x2;
   [Constant]

--- a/dom/webidl/SVGPatternElement.webidl
+++ b/dom/webidl/SVGPatternElement.webidl
@@ -6,17 +6,16 @@
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/pservers.html#InterfaceSVGPatternElement
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
 interface SVGAnimatedEnumeration;
-interface SVGAnimatedLength;
 
 interface SVGPatternElement : SVGElement {
   [Constant]
   readonly attribute SVGAnimatedEnumeration patternUnits;
   [Constant]
   readonly attribute SVGAnimatedEnumeration patternContentUnits;
   [Constant]
   readonly attribute SVGAnimatedTransformList patternTransform;

--- a/dom/webidl/SVGRectElement.webidl
+++ b/dom/webidl/SVGRectElement.webidl
@@ -5,18 +5,16 @@
  *
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
-interface SVGAnimatedLength;
-
 interface SVGRectElement : SVGGraphicsElement {
   [Constant]
   readonly attribute SVGAnimatedLength x;
   [Constant]
   readonly attribute SVGAnimatedLength y;
   [Constant]
   readonly attribute SVGAnimatedLength width;
   [Constant]

--- a/dom/webidl/SVGSVGElement.webidl
+++ b/dom/webidl/SVGSVGElement.webidl
@@ -6,17 +6,16 @@
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
 interface SVGAnimatedString;
-interface SVGAnimatedLength;
 interface SVGViewSpec;
 interface SVGPoint;
 interface SVGRect;
 
 interface SVGSVGElement : SVGGraphicsElement {
 
   readonly attribute SVGAnimatedLength x;
   readonly attribute SVGAnimatedLength y;

--- a/dom/webidl/SVGTextPathElement.webidl
+++ b/dom/webidl/SVGTextPathElement.webidl
@@ -5,17 +5,16 @@
  *
  * The origin of this IDL file is
  * http://www.w3.org/TR/SVG2/
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
-interface SVGAnimatedLength;
 interface SVGAnimatedEnumeration;
 
 interface SVGTextPathElement : SVGTextContentElement {
 
   // textPath Method Types
   const unsigned short TEXTPATH_METHODTYPE_UNKNOWN = 0;
   const unsigned short TEXTPATH_METHODTYPE_ALIGN = 1;
   const unsigned short TEXTPATH_METHODTYPE_STRETCH = 2;

--- a/dom/webidl/WebIDL.mk
+++ b/dom/webidl/WebIDL.mk
@@ -98,16 +98,17 @@ webidl_files = \
   Rect.webidl \
   RGBColor.webidl \
   Screen.webidl \
   SVGAElement.webidl \
   SVGAltGlyphElement.webidl \
   SVGAngle.webidl \
   SVGAnimatedAngle.webidl \
   SVGAnimatedBoolean.webidl \
+  SVGAnimatedLength.webidl \
   SVGAnimatedLengthList.webidl \
   SVGAnimatedNumberList.webidl \
   SVGAnimatedPathData.webidl \
   SVGAnimatedPoints.webidl \
   SVGAnimatedPreserveAspectRatio.webidl \
   SVGAnimatedTransformList.webidl \
   SVGAnimateElement.webidl \
   SVGAnimateMotionElement.webidl \