diff --git a/content/svg/content/src/nsSVGAnimationElement.cpp b/content/svg/content/src/nsSVGAnimationElement.cpp
index e2998504817..055a56e1434 100644
--- a/content/svg/content/src/nsSVGAnimationElement.cpp
+++ b/content/svg/content/src/nsSVGAnimationElement.cpp
@@ -361,6 +361,28 @@ nsSVGAnimationElement::GetTimeContainer()
   return result;
 }
 
+nsIContent*
+nsSVGAnimationElement::GetParentElement()
+{
+  nsCOMPtr<nsIContent> result;
+  nsBindingManager*   bindingManager = nsnull;
+  nsIDocument*        ownerDoc = GetOwnerDoc();
+
+  if (ownerDoc)
+    bindingManager = ownerDoc->BindingManager();
+
+  if (bindingManager)
+    // we have a binding manager -- do we have an anonymous parent?
+    result = bindingManager->GetInsertionParent(this);
+
+  if (!result)
+    // if we didn't find an anonymous parent, use the explicit one,
+    // whether it's null or not...
+    result = GetParent();
+
+  return result;
+}
+
 // nsIDOMElementTimeControl
 /* void beginElement (); */
 NS_IMETHODIMP
diff --git a/content/svg/content/src/nsSVGAnimationElement.h b/content/svg/content/src/nsSVGAnimationElement.h
index effc6461619..8fc2b28229b 100644
--- a/content/svg/content/src/nsSVGAnimationElement.h
+++ b/content/svg/content/src/nsSVGAnimationElement.h
@@ -91,6 +91,9 @@ public:
   virtual nsSMILTimeContainer* GetTimeContainer();
 
 protected:
+  // Implementation helpers
+  nsIContent* GetParentElement();
+
   nsSMILTimedElement   mTimedElement;
   nsSMILTimeContainer* mTimedDocumentRoot;
 };
diff --git a/content/svg/content/src/nsSVGElement.cpp b/content/svg/content/src/nsSVGElement.cpp
index 6dbcae542e3..2967930b8f3 100644
--- a/content/svg/content/src/nsSVGElement.cpp
+++ b/content/svg/content/src/nsSVGElement.cpp
@@ -197,35 +197,6 @@ NS_INTERFACE_MAP_END_INHERITING(nsSVGElementBase)
 //----------------------------------------------------------------------
 // Implementation
   
-nsIContent*
-nsSVGElement::GetParentElement()
-{
-  nsCOMPtr<nsIContent> result;
-
-  nsBindingManager*   bindingManager = nsnull;
-  // XXXbz I _think_ this is right.  We want to be using the binding manager
-  // that would have attached the binding that gives us our anonymous parent.
-  // That's the binding manager for the document we actually belong to, which
-  // is our owner doc.
-  nsIDocument* ownerDoc = GetOwnerDoc();
-  if (ownerDoc) {
-    bindingManager = ownerDoc->BindingManager();
-  }
-
-  if (bindingManager) {
-    // we have a binding manager -- do we have an anonymous parent?
-    result = bindingManager->GetInsertionParent(this);
-  }
-
-  if (!result) {
-    // if we didn't find an anonymous parent, use the explicit one,
-    // whether it's null or not...
-    result = GetParent();
-  }
-
-  return result;
-}
-
 //----------------------------------------------------------------------
 // nsIContent methods
 
@@ -291,8 +262,22 @@ nsSVGElement::AfterSetAttr(PRInt32 aNamespaceID, nsIAtom* aName,
        aName == nsGkAtoms::requiredExtensions ||
        aName == nsGkAtoms::systemLanguage)) {
 
-    nsIContent* parent = GetParentElement();
+    nsIContent* parent = nsnull;
   
+    nsIContent* bindingParent = GetBindingParent();
+    if (bindingParent) {
+      nsIDocument* doc = bindingParent->GetOwnerDoc();
+      if (doc) {
+        parent = doc->BindingManager()->GetInsertionParent(bindingParent);
+      }
+    }
+
+    if (!parent) {
+      // if we didn't find an anonymous parent, use the explicit one,
+      // whether it's null or not...
+      parent = GetParent();
+    }
+
     if (parent &&
         parent->NodeInfo()->Equals(nsGkAtoms::svgSwitch, kNameSpaceID_SVG)) {
       static_cast<nsSVGSwitchElement*>(parent)->MaybeInvalidate();
diff --git a/content/svg/content/src/nsSVGElement.h b/content/svg/content/src/nsSVGElement.h
index 14e16b3b918..48bd69a6646 100644
--- a/content/svg/content/src/nsSVGElement.h
+++ b/content/svg/content/src/nsSVGElement.h
@@ -134,12 +134,10 @@ public:
   // nsISupportsWeakReference
   // implementation inherited from nsSupportsWeakReference
 
-  nsIContent* GetParentElement();
-
   // Gets the element that establishes the rectangular viewport against which
   // we should resolve percentage lengths (our "coordinate context"). Returns
-  // nsnull SVG without an <svg> parent (invalid SVG).
-  virtual nsSVGSVGElement* GetCtx();
+  // nsnull for outer <svg> or SVG without an <svg> parent (invalid SVG).
+  nsSVGSVGElement* GetCtx();
 
   virtual void DidChangeLength(PRUint8 aAttrEnum, PRBool aDoSetAttr);
   virtual void DidChangeNumber(PRUint8 aAttrEnum, PRBool aDoSetAttr);
diff --git a/content/svg/content/src/nsSVGLength.cpp b/content/svg/content/src/nsSVGLength.cpp
index 330e9f1cfb7..f17c84df36c 100644
--- a/content/svg/content/src/nsSVGLength.cpp
+++ b/content/svg/content/src/nsSVGLength.cpp
@@ -58,9 +58,14 @@ class nsSVGLength : public nsISVGLength,
                     public nsSVGValue
 {
 protected:
+  friend nsresult NS_NewSVGLength(nsISVGLength** result,
+                                  float value,
+                                  PRUint16 unit);
+
   friend nsresult NS_NewSVGLength(nsISVGLength** result,
                                   const nsAString &value);
   
+  nsSVGLength(float value, PRUint16 unit);
   nsSVGLength();
 
 public:
@@ -98,6 +103,18 @@ protected:
 //----------------------------------------------------------------------
 // Implementation
 
+nsresult
+NS_NewSVGLength(nsISVGLength** result,
+                float value,
+                PRUint16 unit)
+{
+  *result = new nsSVGLength(value, unit);
+  if (!*result)
+    return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(*result);
+  return NS_OK;
+}
+
 nsresult
 NS_NewSVGLength(nsISVGLength** result,
                 const nsAString &value)
@@ -117,6 +134,14 @@ NS_NewSVGLength(nsISVGLength** result,
 }  
 
 
+nsSVGLength::nsSVGLength(float value,
+                         PRUint16 unit)
+    : mValueInSpecifiedUnits(value),
+      mSpecifiedUnitType(unit),
+      mCtxType(0)
+{
+}
+
 nsSVGLength::nsSVGLength()
 {
 }
diff --git a/content/svg/content/src/nsSVGLength.h b/content/svg/content/src/nsSVGLength.h
index d69f402aff7..cf30725ae9e 100644
--- a/content/svg/content/src/nsSVGLength.h
+++ b/content/svg/content/src/nsSVGLength.h
@@ -42,8 +42,18 @@
 #include "nsISVGLength.h"
 #include "nsAString.h"
 
+nsresult
+NS_NewSVGLength(nsISVGLength** result,
+                float value=0.0f,
+                PRUint16 unit=nsIDOMSVGLength::SVG_LENGTHTYPE_NUMBER);
+
 nsresult
 NS_NewSVGLength(nsISVGLength** result,
                 const nsAString &value);
 
+// XXX we'll need this prototype-based stuff to support unsetting:
+//nsresult NS_NewSVGLength(nsIDOMSVGLength** result,
+//                         nsIDOMSVGLength*  prototype);
+
+
 #endif //__NS_SVGLENGTH_H__
diff --git a/content/svg/content/src/nsSVGLength2.cpp b/content/svg/content/src/nsSVGLength2.cpp
index 700a53ad7ee..ff2bc18cf5e 100644
--- a/content/svg/content/src/nsSVGLength2.cpp
+++ b/content/svg/content/src/nsSVGLength2.cpp
@@ -36,6 +36,7 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
+#include "nsISVGLength.h"
 #include "nsSVGLength2.h"
 #include "prdtoa.h"
 #include "nsTextFormatter.h"
@@ -47,56 +48,12 @@
 #include "nsSMILFloatType.h"
 #endif // MOZ_SMIL
 
-class DOMSVGLength : public nsIDOMSVGLength
-{
-public:
-  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-  NS_DECL_CYCLE_COLLECTION_CLASS(DOMSVGLength)
-
-  DOMSVGLength(nsSVGElement *aSVGElement)
-    : mSVGElement(aSVGElement)
-    { mVal.Init(); }
-    
-  NS_IMETHOD GetUnitType(PRUint16* aResult)
-    { *aResult = mVal.mSpecifiedUnitType; return NS_OK; }
-
-  NS_IMETHOD GetValue(float* aResult)
-    { *aResult = mVal.GetBaseValue(mSVGElement); return NS_OK; }
-  NS_IMETHOD SetValue(float aValue)
-    { NS_ENSURE_FINITE(aValue, NS_ERROR_ILLEGAL_VALUE);
-      mVal.mBaseVal = 
-        aValue * mVal.GetUnitScaleFactor(mSVGElement, mVal.mSpecifiedUnitType);
-      return NS_OK; }
-
-  NS_IMETHOD GetValueInSpecifiedUnits(float* aResult)
-    { *aResult = mVal.mBaseVal; return NS_OK; }
-  NS_IMETHOD SetValueInSpecifiedUnits(float aValue)
-    { NS_ENSURE_FINITE(aValue, NS_ERROR_ILLEGAL_VALUE);
-      mVal.mBaseVal = aValue;
-      return NS_OK; }
-
-  NS_IMETHOD SetValueAsString(const nsAString& aValueAsString);
-  NS_IMETHOD GetValueAsString(nsAString& aValue)
-    { mVal.GetBaseValueString(aValue); return NS_OK; }
-
-  NS_IMETHOD NewValueSpecifiedUnits(PRUint16 unitType,
-                                    float valueInSpecifiedUnits);
-
-  NS_IMETHOD ConvertToSpecifiedUnits(PRUint16 unitType);
-
-private:
-  nsSVGLength2 mVal;
-  nsRefPtr<nsSVGElement> mSVGElement;
-};
-
 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_SVG_VAL_IMPL_CYCLE_COLLECTION(DOMSVGLength, mSVGElement)
-
 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsSVGLength2::DOMBaseVal)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsSVGLength2::DOMBaseVal)
 
@@ -106,9 +63,6 @@ NS_IMPL_CYCLE_COLLECTING_RELEASE(nsSVGLength2::DOMAnimVal)
 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsSVGLength2::DOMAnimatedLength)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsSVGLength2::DOMAnimatedLength)
 
-NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMSVGLength)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMSVGLength)
-
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsSVGLength2::DOMBaseVal)
   NS_INTERFACE_MAP_ENTRY(nsIDOMSVGLength)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
@@ -127,12 +81,6 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsSVGLength2::DOMAnimatedLength)
   NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(SVGAnimatedLength)
 NS_INTERFACE_MAP_END
 
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMSVGLength)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMSVGLength)
-  NS_INTERFACE_MAP_ENTRY(nsISupports)
-  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(SVGLength)
-NS_INTERFACE_MAP_END
-
 static nsIAtom** const unitMap[] =
 {
   nsnull, /* SVG_LENGTHTYPE_UNKNOWN */
@@ -228,49 +176,6 @@ GetValueFromString(const nsAString &aValueAsString,
   return NS_ERROR_FAILURE;
 }
 
-NS_IMETHODIMP
-DOMSVGLength::SetValueAsString(const nsAString& aValueAsString)
-{
-  float value;
-  PRUint16 unitType;
-  
-  nsresult rv = GetValueFromString(aValueAsString, &value, &unitType);
-  if (NS_FAILED(rv)) {
-    return rv;
-  }
-  
-  mVal.mBaseVal = value;
-  mVal.mSpecifiedUnitType = PRUint8(unitType);
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-DOMSVGLength::NewValueSpecifiedUnits(PRUint16 unitType,
-                                     float valueInSpecifiedUnits)
-{
-  NS_ENSURE_FINITE(valueInSpecifiedUnits, NS_ERROR_ILLEGAL_VALUE);
-  if (!IsValidUnitType(unitType))
-    return NS_OK;
-
-  mVal.mBaseVal = valueInSpecifiedUnits;
-  mVal.mSpecifiedUnitType = PRUint8(unitType);
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-DOMSVGLength::ConvertToSpecifiedUnits(PRUint16 unitType)
-{
-  if (!IsValidUnitType(unitType))
-    return NS_OK;
-
-  float valueInUserUnits = 
-    mVal.mBaseVal / mVal.GetUnitScaleFactor(mSVGElement, mVal.mSpecifiedUnitType);
-  mVal.mSpecifiedUnitType = PRUint8(unitType);
-  mVal.mBaseVal = 
-    valueInUserUnits * mVal.GetUnitScaleFactor(mSVGElement, mVal.mSpecifiedUnitType);
-  return NS_OK;
-}
-
 float
 nsSVGLength2::GetMMPerPixel(nsSVGSVGElement *aCtx) const
 {
@@ -554,17 +459,6 @@ nsSVGLength2::ToDOMAnimatedLength(nsIDOMSVGAnimatedLength **aResult,
   return NS_OK;
 }
 
-nsresult
-NS_NewDOMSVGLength(nsIDOMSVGLength** aResult, nsSVGElement *aSVGElement)
-{
-  *aResult = new DOMSVGLength(aSVGElement);
-  if (!*aResult)
-    return NS_ERROR_OUT_OF_MEMORY;
-
-  NS_ADDREF(*aResult);
-  return NS_OK;
-}
-
 #ifdef MOZ_SMIL
 nsISMILAttr*
 nsSVGLength2::ToSMILAttr(nsSVGElement *aSVGElement)
diff --git a/content/svg/content/src/nsSVGLength2.h b/content/svg/content/src/nsSVGLength2.h
index 5463efb9085..84d077752a9 100644
--- a/content/svg/content/src/nsSVGLength2.h
+++ b/content/svg/content/src/nsSVGLength2.h
@@ -53,7 +53,6 @@ class nsIFrame;
 
 class nsSVGLength2
 {
-  friend class DOMSVGLength;
 
 public:
   void Init(PRUint8 aCtxType = nsSVGUtils::XY,
@@ -290,7 +289,4 @@ private:
 #endif // MOZ_SMIL
 };
 
-nsresult
-NS_NewDOMSVGLength(nsIDOMSVGLength** result, nsSVGElement *aSVGElement);
-
 #endif //  __NS_SVGLENGTH2_H__
diff --git a/content/svg/content/src/nsSVGNumber2.cpp b/content/svg/content/src/nsSVGNumber2.cpp
index 95ab757e982..5750f49ecac 100644
--- a/content/svg/content/src/nsSVGNumber2.cpp
+++ b/content/svg/content/src/nsSVGNumber2.cpp
@@ -129,13 +129,3 @@ nsSVGNumber2::ToDOMAnimatedNumber(nsIDOMSVGAnimatedNumber **aResult,
   return NS_OK;
 }
 
-nsresult
-NS_NewDOMSVGNumber(nsIDOMSVGNumber** aResult)
-{
-  *aResult = new DOMSVGNumber();
-  if (!*aResult)
-    return NS_ERROR_OUT_OF_MEMORY;
-
-  NS_ADDREF(*aResult);
-  return NS_OK;
-}
diff --git a/content/svg/content/src/nsSVGNumber2.h b/content/svg/content/src/nsSVGNumber2.h
index 82f0a9c6357..58aef6cad10 100644
--- a/content/svg/content/src/nsSVGNumber2.h
+++ b/content/svg/content/src/nsSVGNumber2.h
@@ -44,7 +44,6 @@
 
 class nsSVGNumber2
 {
-  friend class DOMSVGNumber;
 
 public:
   void Init(PRUint8 aAttrEnum = 0xff, float aValue = 0) {
@@ -97,8 +96,4 @@ private:
   };
 
 };
-
-nsresult
-NS_NewDOMSVGNumber(nsIDOMSVGNumber** result);
-
 #endif //__NS_SVGNUMBER2_H__
diff --git a/content/svg/content/src/nsSVGSVGElement.cpp b/content/svg/content/src/nsSVGSVGElement.cpp
index 471f7854430..ebbedf7ae42 100644
--- a/content/svg/content/src/nsSVGSVGElement.cpp
+++ b/content/svg/content/src/nsSVGSVGElement.cpp
@@ -39,8 +39,7 @@
  * ***** END LICENSE BLOCK ***** */
 
 #include "nsGkAtoms.h"
-#include "nsSVGNumber2.h"
-#include "nsSVGLength2.h"
+#include "nsSVGLength.h"
 #include "nsSVGAngle.h"
 #include "nsCOMPtr.h"
 #include "nsIPresShell.h"
@@ -180,15 +179,6 @@ nsSVGSVGElement::Init()
   return rv;
 }
 
-PRBool
-nsSVGSVGElement::IsOutermostSVGElement()
-{
-  nsIContent *parent = GetParentElement();
-
-  return !parent || parent->GetNameSpaceID() != kNameSpaceID_SVG ||
-         parent->Tag() == nsGkAtoms::foreignObject;
-}
-
 //----------------------------------------------------------------------
 // nsIDOMNode methods
 
@@ -633,14 +623,14 @@ nsSVGSVGElement::DeSelectAll()
 NS_IMETHODIMP
 nsSVGSVGElement::CreateSVGNumber(nsIDOMSVGNumber **_retval)
 {
-  return NS_NewDOMSVGNumber(_retval);
+  return NS_NewSVGNumber(_retval);
 }
 
 /* nsIDOMSVGLength createSVGLength (); */
 NS_IMETHODIMP
 nsSVGSVGElement::CreateSVGLength(nsIDOMSVGLength **_retval)
 {
-  return NS_NewDOMSVGLength(_retval, this);
+  return NS_NewSVGLength(reinterpret_cast<nsISVGLength**>(_retval));
 }
 
 /* nsIDOMSVGAngle createSVGAngle (); */
@@ -1292,7 +1282,7 @@ nsSVGSVGElement::GetViewboxToViewportTransform(nsIDOMSVGMatrix **_retval)
 
   float viewportWidth, viewportHeight;
   nsSVGSVGElement *ctx = GetCtx();
-  if (ctx == this) {
+  if (!ctx) {
     // outer svg
     viewportWidth = mViewportWidth;
     viewportHeight = mViewportHeight;
@@ -1477,13 +1467,12 @@ nsSVGSVGElement::GetLength(PRUint8 aCtxType)
     h = viewbox.height;
   } else {
     nsSVGSVGElement *ctx = GetCtx();
-    if (ctx == this) {
-      // outer svg
-      w = mViewportWidth;
-      h = mViewportHeight;
-    } else {
+    if (ctx) {
       w = mLengthAttributes[WIDTH].GetAnimValue(ctx);
       h = mLengthAttributes[HEIGHT].GetAnimValue(ctx);
+    } else {
+      w = mViewportWidth;
+      h = mViewportHeight;
     }
   }
 
diff --git a/content/svg/content/src/nsSVGSVGElement.h b/content/svg/content/src/nsSVGSVGElement.h
index 5f3dca66fae..eaa65b11a65 100644
--- a/content/svg/content/src/nsSVGSVGElement.h
+++ b/content/svg/content/src/nsSVGSVGElement.h
@@ -104,12 +104,6 @@ public:
   NS_FORWARD_NSIDOMELEMENT(nsSVGSVGElementBase::)
   NS_FORWARD_NSIDOMSVGELEMENT(nsSVGSVGElementBase::)
 
-  // Gets the element that establishes the rectangular viewport against which
-  // we should resolve percentage lengths (our "coordinate context").
-  virtual nsSVGSVGElement* GetCtx() {
-    return IsOutermostSVGElement() ? this : nsSVGSVGElementBase::GetCtx();
-  }
-
   // helper methods for implementing SVGZoomEvent:
   nsresult GetCurrentScaleNumber(nsIDOMSVGNumber **aResult);
 
@@ -168,8 +162,6 @@ public:
   float GetMMPerPx(PRUint8 mCtxType = 0);
 
   // public helpers:
-  PRBool IsOutermostSVGElement();
-
   nsresult GetViewboxToViewportTransform(nsIDOMSVGMatrix **_retval);
 
   virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
diff --git a/content/svg/content/test/Makefile.in b/content/svg/content/test/Makefile.in
index d45790a1d9f..705f50067bf 100644
--- a/content/svg/content/test/Makefile.in
+++ b/content/svg/content/test/Makefile.in
@@ -55,7 +55,6 @@ _TEST_FILES = \
 		test_pathSeg.xhtml \
 		test_scientific.html \
 		scientific-helper.svg \
-		test_length.xhtml \
 		test_text.html \
 		text-helper.svg \
 		test_valueLeaks.xhtml \