--- a/layout/svg/nsSVGClipPathFrame.cpp
+++ b/layout/svg/nsSVGClipPathFrame.cpp
@@ -222,18 +222,17 @@ nsSVGClipPathFrame::GetClipMask(gfxConte
 
     RefPtr<SourceSurface> currentMask = maskDT->Snapshot();
     maskDT->SetTransform(Matrix());
     maskDT->ClearRect(Rect(0, 0,
                            devSpaceClipExtents.width,
                            devSpaceClipExtents.height));
     maskDT->MaskSurface(SurfacePattern(currentMask, ExtendMode::CLAMP),
                         aExtraMask,
-                        Point(aExtraMasksTransform._31 - devSpaceClipExtents.x,
-                              aExtraMasksTransform._32 - devSpaceClipExtents.y));
+                        Point(aExtraMasksTransform._31, aExtraMasksTransform._32));
   }
 
   *aMaskTransform = ToMatrix(mat);
   return maskDT->Snapshot();
 }
 
 bool
 nsSVGClipPathFrame::PointIsInsideClipPath(nsIFrame* aClippedFrame,