Make HTMLAllCollection named property getter behave more according to spec

Source/core/html/HTMLAllCollection.idl

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
+ * Copyright (C) 2014 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 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.
  */
 
+// FIXME: This interface should inherit HTMLCollection.
 [
     Custom=LegacyCallAsFunction,
     DependentLifetime,
     SetWrapperReferenceFrom=ownerNode,
 ] interface HTMLAllCollection {
     readonly attribute unsigned long length;
     [ImplementedAs=item] getter Element (unsigned long index);
     [Custom] Element item([Default=Undefined] optional unsigned long index);
-    [NotEnumerable] getter (NodeList or Element) (DOMString name);
-    [Custom] Element namedItem(DOMString name);
+    // FIXME: This should return an (HTMLCollection or Element) union.
+    [ImplementedAs=namedGetter] getter (NodeList or Element) namedItem(DOMString name);
 };