Fix problems with flakes in SVG LayoutTests by reordering arithmetic.

Source/core/svg/SVGLength.h

Index: Source/core/svg/SVGLength.h
diff --git a/Source/core/svg/SVGLength.h b/Source/core/svg/SVGLength.h
index b7986d34dc16c64c27c43008ced8a2c3ad994e5d..41a3eb64256ffa16c811250e9208146563f79b51 100644
--- a/Source/core/svg/SVGLength.h
+++ b/Source/core/svg/SVGLength.h
@@ -69,8 +69,15 @@ public:
     float valueInSpecifiedUnits() const { return m_valueInSpecifiedUnits; }
     void setValueInSpecifiedUnits(float value) { m_valueInSpecifiedUnits = value; }
 
+    // Resolves LengthTypePercentage into a normalized floating point number (full value is 1.0).
     float valueAsPercentage() const;
 
+    // Returns a number to be used as percentage (so full value is 100)
+    float valueAsPercentage100() const;
+
+    // Scale the input value by this SVGLength. Higher precision than input * valueAsPercentage().
+    float scaleByPercentage(float) const;
+
     virtual String valueAsString() const override;
     void setValueAsString(const String&, ExceptionState&);