Make several DOMImplementation API arguments mandatory

Source/core/dom/DOMImplementation.idl

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * 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.
  */
 
 [
     GenerateIsReachable=document
 ] interface DOMImplementation {
 
     // DOM Level 1
 
-     boolean hasFeature([Default=Undefined] optional DOMString feature,
-                                      [TreatNullAs=NullString,Default=Undefined] optional DOMString version);
+     boolean hasFeature(DOMString feature, [TreatNullAs=NullString] DOMString version);

[arv (Not doing code reviews), 2013/08/14 15:08:22]

These changes make little sense. A nullable param in tail position is ripe for
being optional.

I'll file dom spec bugs

 
     // DOM Level 2
 
-     [RaisesException] DocumentType createDocumentType([TreatNullAs=NullString, TreatUndefinedAs=NullString,Default=Undefined] optional DOMString qualifiedName,
-                                                   [TreatNullAs=NullString, TreatUndefinedAs=NullString,Default=Undefined] optional DOMString publicId,
-                                                   [TreatNullAs=NullString, TreatUndefinedAs=NullString,Default=Undefined] optional DOMString systemId);
-     [RaisesException] Document createDocument([TreatNullAs=NullString,Default=Undefined] optional DOMString namespaceURI,
-                                           [TreatNullAs=NullString,Default=Undefined] optional DOMString qualifiedName,
-                                           [TreatNullAs=NullString,Default=Undefined] optional DocumentType doctype);
+     [RaisesException] DocumentType createDocumentType([TreatNullAs=NullString] DOMString qualifiedName,
+                                                       [TreatNullAs=NullString] DOMString publicId,
+                                                       [TreatNullAs=NullString] DOMString systemId);
+     [RaisesException] Document createDocument([TreatNullAs=NullString] DOMString namespaceURI,

[arv (Not doing code reviews), 2013/08/14 15:08:22]

I'm concerned about this one. I've seen people call this with less than 3
arguments (in webkit specific code but still).

[do-not-use, 2013/08/14 15:43:02]

I agree that the last argument could be optional since it is already nullable.

However, I believe the first argument only makes sense if the second one is
given. Also note that currently, if you omit the second argument
(qualifiedName), it will create a documentElement for the document with the
"undefined" string as tagName. This is unlikely to be what the caller wants IMO.

If we don't want to comply with the spec, I think we should add least add
[TreatUndefinedAs=NullString] for the second argument to avoid this weird
behavior.

+                                               [TreatNullAs=NullString] DOMString qualifiedName,
+                                               DocumentType doctype);
 
     // DOMImplementationCSS interface from DOM Level 2 CSS
 
      CSSStyleSheet createCSSStyleSheet([Default=Undefined] optional DOMString title,
                                        [Default=Undefined] optional DOMString media);
 
     // HTMLDOMImplementation interface from DOM Level 2 HTML
 
     HTMLDocument createHTMLDocument([Default=NullString] optional DOMString title);
 };