Remove meaningless uses of [TypeChecking=Nullable]

Source/core/svg/SVGGraphicsElement.idl

 /*
  * Copyright (C) 2013 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // http://www.w3.org/TR/SVG2/types.html#InterfaceSVGGraphicsElement
 
 [
-    TypeChecking=Interface|Nullable,
+    TypeChecking=Interface,
 ] interface SVGGraphicsElement : SVGElement {
     readonly attribute SVGAnimatedTransformList transform;
 
     [MeasureAs=SVGLocatableNearestViewportElement] readonly attribute SVGElement nearestViewportElement;
     [MeasureAs=SVGLocatableFarthestViewportElement] readonly attribute SVGElement farthestViewportElement;
 
     [ImplementedAs=getBBoxFromJavascript] SVGRect getBBox();
     [ImplementedAs=getCTMFromJavascript] SVGMatrix getCTM();
     [ImplementedAs=getScreenCTMFromJavascript] SVGMatrix getScreenCTM();
     [RaisesException] SVGMatrix getTransformToElement(SVGElement element);
 };
 
 SVGGraphicsElement implements SVGTests;