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

Source/core/svg/SVGLength.idl

 /*
  * Copyright (C) 2004, 2005, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  * Copyright (C) 2006 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * 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;
     const unsigned short SVG_LENGTHTYPE_PERCENTAGE = 2;
     const unsigned short SVG_LENGTHTYPE_EMS        = 3;
     const unsigned short SVG_LENGTHTYPE_EXS        = 4;
     const unsigned short SVG_LENGTHTYPE_PX         = 5;
     const unsigned short SVG_LENGTHTYPE_CM         = 6;
     const unsigned short SVG_LENGTHTYPE_MM         = 7;
     const unsigned short SVG_LENGTHTYPE_IN         = 8;
     const unsigned short SVG_LENGTHTYPE_PT         = 9;
     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);
 };