Add null-correctness checking to [StrictTypeChecking] methods

Source/core/svg/SVGTransformList.idl

 /*
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  * Copyright (C) 2006 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 10 matching lines @@
  * 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.
  */
 
 interface SVGTransformList {
     readonly attribute unsigned long numberOfItems;
 
     [RaisesException] void clear();
-    [StrictTypeChecking, RaisesException] SVGTransform initialize(SVGTransform item);
+    [StrictTypeChecking, RaisesException] SVGTransform initialize(SVGTransform? item);
     [StrictTypeChecking, RaisesException] SVGTransform getItem(unsigned long index);
-    [StrictTypeChecking, RaisesException] SVGTransform insertItemBefore(SVGTransform item, unsigned long index);
-    [StrictTypeChecking, RaisesException] SVGTransform replaceItem(SVGTransform item, unsigned long index);
+    [StrictTypeChecking, RaisesException] SVGTransform insertItemBefore(SVGTransform? item, unsigned long index);
+    [StrictTypeChecking, RaisesException] SVGTransform replaceItem(SVGTransform? item, unsigned long index);
     [StrictTypeChecking, RaisesException] SVGTransform removeItem(unsigned long index);
-    [StrictTypeChecking, RaisesException] SVGTransform appendItem(SVGTransform item);
+    [StrictTypeChecking, RaisesException] SVGTransform appendItem(SVGTransform? item);
 
-    [StrictTypeChecking, RaisesException] SVGTransform createSVGTransformFromMatrix(SVGMatrix matrix);
+    [StrictTypeChecking, RaisesException] SVGTransform createSVGTransformFromMatrix(SVGMatrix? matrix);
 
     [RaisesException] SVGTransform consolidate();
 };