[SVG] SVGLength{,List} migration to new SVG property impl.

Source/core/svg/SVGLength.idl

Index: Source/core/svg/SVGLength.idl
diff --git a/Source/core/svg/SVGLength.idl b/Source/core/svg/SVGLength.idl
index 4d29af7ffa441373471a79ed3075c3f0ecdf49bb..e5af1f9f302d6ee2a2bd0719b5a0667f3b8bdced 100644
--- a/Source/core/svg/SVGLength.idl
+++ b/Source/core/svg/SVGLength.idl
@@ -20,7 +20,10 @@
  * Boston, MA 02110-1301, USA.
  */
 
-interface SVGLength {
+[
+    ImplementedAs=SVGLengthTearOff,
+    SetReference(SVGElement contextElement)
+] interface SVGLength {
     // Length Unit Types
     const unsigned short SVG_LENGTHTYPE_UNKNOWN    = 0;
     const unsigned short SVG_LENGTHTYPE_NUMBER     = 1;
@@ -35,14 +38,14 @@ interface SVGLength {
     const unsigned short SVG_LENGTHTYPE_PC         = 10;
 
     readonly attribute unsigned short unitType;
-    [Custom, StrictTypeChecking, RaisesException] attribute float value;
+    [StrictTypeChecking, RaisesException] attribute float value;
 
-    [StrictTypeChecking] attribute float valueInSpecifiedUnits;
+    [StrictTypeChecking, RaisesException=Setter] attribute float valueInSpecifiedUnits;
     [TreatNullAs=NullString, StrictTypeChecking, RaisesException=Setter] attribute DOMString valueAsString;
 
     [StrictTypeChecking, RaisesException] void newValueSpecifiedUnits(unsigned short unitType,
                                                      float valueInSpecifiedUnits);
 
-    [Custom, StrictTypeChecking, RaisesException] void convertToSpecifiedUnits(unsigned short unitType);
+    [StrictTypeChecking, RaisesException] void convertToSpecifiedUnits(unsigned short unitType);
 };