Sync execCommand() and queryCommand*() IDL with spec

Source/core/dom/Document.idl

 /*
  * Copyright (C) 2006, 2007, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006, 2007 Samuel Weinig <sam@webkit.org>
  *
  * 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,
@@ skipping 75 matching lines @@
 
     // DOM Level 2 Style (DocumentCSS interface)
 
     [MeasureAs=DocumentGetOverrideStyle] CSSStyleDeclaration getOverrideStyle();
 
     // DOM 4
     readonly attribute DOMString contentType;
 
     // Common extensions
     [CustomElementCallbacks]
-    boolean            execCommand([Default=Undefined] optional DOMString command,
-                                   [Default=Undefined] optional boolean userInterface,
-                                   [TreatUndefinedAs=NullString, Default=Undefined] optional DOMString? value);
-
-    boolean            queryCommandEnabled([Default=Undefined] optional DOMString command);
-    boolean            queryCommandIndeterm([Default=Undefined] optional DOMString command);
-    boolean            queryCommandState([Default=Undefined] optional DOMString command);
-    boolean            queryCommandSupported([Default=Undefined] optional DOMString command);
-    DOMString          queryCommandValue([Default=Undefined] optional DOMString command);
+    boolean execCommand(DOMString command, optional boolean showUI = false, optional DOMString value = "");
+    boolean queryCommandEnabled(DOMString command);
+    boolean queryCommandIndeterm(DOMString command);
+    boolean queryCommandState(DOMString command);
+    boolean queryCommandSupported(DOMString command);
+    DOMString queryCommandValue(DOMString command);
 
     // Moved down from HTMLDocument
              [TreatNullAs=NullString, CustomElementCallbacks] attribute DOMString dir;
              [TreatNullAs=NullString, CustomElementCallbacks] attribute DOMString designMode;
              [TreatNullAs=NullString, CustomElementCallbacks] attribute DOMString title;
     readonly attribute DOMString referrer;
              [TreatNullAs=NullString, RaisesException=Setter] attribute DOMString domain;
     readonly attribute DOMString URL;
 
              [TreatNullAs=NullString, RaisesException] attribute DOMString cookie;
@@ skipping 92 matching lines @@
     // TODO(davidben): This is a property so attaching a deprecation warning results in false positives when outputting
     // document in the console. It's possible http://crbug.com/43394 will resolve this.
     [MeasureAs=PrefixedPageVisibility, ImplementedAs=visibilityState] readonly attribute DOMString webkitVisibilityState;
     [MeasureAs=PrefixedPageVisibility, ImplementedAs=hidden] readonly attribute boolean webkitHidden;
 
     readonly attribute HTMLScriptElement currentScript;
 };
 
 Document implements GlobalEventHandlers;
 Document implements ParentNode;