diff --git a/layout/style/nsStyleCoord.h b/layout/style/nsStyleCoord.h
index 0c8dab67a28..725dc573d59 100644
--- a/layout/style/nsStyleCoord.h
+++ b/layout/style/nsStyleCoord.h
@@ -143,6 +143,11 @@ public:
            (IsCalcUnit() && CalcHasPercent());
   }
 
+  PRBool ConvertsToLength() const {
+    return mUnit == eStyleUnit_Coord ||
+           (IsCalcUnit() && !CalcHasPercent());
+  }
+
   nscoord     GetCoordValue() const;
   PRInt32     GetIntValue() const;
   float       GetPercentValue() const;
diff --git a/layout/svg/base/src/nsSVGOuterSVGFrame.cpp b/layout/svg/base/src/nsSVGOuterSVGFrame.cpp
index 5b583efc6b4..498b5e43c93 100644
--- a/layout/svg/base/src/nsSVGOuterSVGFrame.cpp
+++ b/layout/svg/base/src/nsSVGOuterSVGFrame.cpp
@@ -480,10 +480,8 @@ DependsOnIntrinsicSize(const nsIFrame* aEmbeddingFrame)
   // XXX it would be nice to know if the size of aEmbeddingFrame's containing
   // block depends on aEmbeddingFrame, then we'd know if we can return false
   // for eStyleUnit_Percent too.
-  return (width.GetUnit() != eStyleUnit_Coord &&
-          (!width.IsCalcUnit() || width.CalcHasPercent())) ||
-         (height.GetUnit() != eStyleUnit_Coord &&
-          (!height.IsCalcUnit() || height.CalcHasPercent()));
+  return !width.ConvertsToLength() ||
+         !height.ConvertsToLength();
 }
 
 NS_IMETHODIMP