--- a/dom/svg/SVGSVGElement.cpp
+++ b/dom/svg/SVGSVGElement.cpp
@@ -183,39 +183,17 @@ SVGSVGElement::Width()
   return mLengthAttributes[ATTR_WIDTH].ToDOMAnimatedLength(this);
 }
 
 already_AddRefed<SVGAnimatedLength>
 SVGSVGElement::Height()
 {
   return mLengthAttributes[ATTR_HEIGHT].ToDOMAnimatedLength(this);
 }
-float
-SVGSVGElement::PixelUnitToMillimeterX()
-{
-  return MM_PER_INCH_FLOAT / 96;
-}
 
-float
-SVGSVGElement::PixelUnitToMillimeterY()
-{
-  return PixelUnitToMillimeterX();
-}
-
-float
-SVGSVGElement::ScreenPixelToMillimeterX()
-{
-  return MM_PER_INCH_FLOAT / 96;
-}
-
-float
-SVGSVGElement::ScreenPixelToMillimeterY()
-{
-  return ScreenPixelToMillimeterX();
-}
 bool
 SVGSVGElement::UseCurrentView()
 {
   return mSVGView || mCurrentViewID;
 }
 
 float
 SVGSVGElement::CurrentScale()

--- a/dom/svg/SVGSVGElement.h
+++ b/dom/svg/SVGSVGElement.h
@@ -110,20 +110,16 @@ public:
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
                          bool aPreallocateChildren) const override;
 
   // WebIDL
   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();
   float CurrentScale();
   void SetCurrentScale(float aCurrentScale);
   already_AddRefed<nsISVGPoint> CurrentTranslate();
   void SetCurrentTranslate(float x, float y);
   uint32_t SuspendRedraw(uint32_t max_wait_milliseconds);
   void UnsuspendRedraw(uint32_t suspend_handle_id);
   void UnsuspendRedrawAll();

--- a/dom/webidl/SVGSVGElement.webidl
+++ b/dom/webidl/SVGSVGElement.webidl
@@ -18,24 +18,16 @@ interface SVGSVGElement : SVGGraphicsEle
   readonly attribute SVGAnimatedLength x;
   [Constant]
   readonly attribute SVGAnimatedLength y;
   [Constant]
   readonly attribute SVGAnimatedLength width;
   [Constant]
   readonly attribute SVGAnimatedLength height;
   // readonly attribute SVGRect viewport;
-  [Constant]
-  readonly attribute float pixelUnitToMillimeterX;
-  [Constant]
-  readonly attribute float pixelUnitToMillimeterY;
-  [Constant]
-  readonly attribute float screenPixelToMillimeterX;
-  [Constant]
-  readonly attribute float screenPixelToMillimeterY;
   readonly attribute boolean useCurrentView;
   // readonly attribute SVGViewSpec currentView;
   [UseCounter]
            attribute float currentScale;
   readonly attribute SVGPoint currentTranslate;
 
   [DependsOn=Nothing, Affects=Nothing]
   unsigned long suspendRedraw(unsigned long maxWaitMilliseconds);

--- a/testing/web-platform/meta/svg/historical.html.ini
+++ b/testing/web-platform/meta/svg/historical.html.ini
@@ -15,20 +15,8 @@
     expected: FAIL
 
   [SVGSVGElement.prototype.useCurrentView must be removed]
     expected: FAIL
 
   [SVGViewElement.prototype.viewTarget must be removed]
     expected: FAIL
 
-  [SVGSVGElement.prototype.pixelUnitToMillimeterX must be removed]
-    expected: FAIL
-
-  [SVGSVGElement.prototype.pixelUnitToMillimeterY must be removed]
-    expected: FAIL
-
-  [SVGSVGElement.prototype.screenPixelToMillimeterX must be removed]
-    expected: FAIL
-
-  [SVGSVGElement.prototype.screenPixelToMillimeterY must be removed]
-    expected: FAIL
-