Initial patch for the web modules layered platform proposal.

Source/core/dom/Node.idl

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 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,
@@ skipping 30 matching lines @@
     readonly attribute unsigned short nodeType;
     readonly attribute DOMString nodeName;
 
     readonly attribute DOMString? baseURI;
 
     [PerWorldBindings] readonly attribute Document? ownerDocument;
     [PerWorldBindings] readonly attribute Node? parentNode;
     [PerWorldBindings] readonly attribute Element? parentElement;
     [ImplementedAs=hasChildren] boolean hasChildNodes();
     [SameObject, PerWorldBindings] readonly attribute NodeList childNodes;
-    [PerWorldBindings] readonly attribute Node? firstChild;
+    [PerWorldBindings, WebModulesExposed] readonly attribute Node? firstChild;
     [PerWorldBindings] readonly attribute Node? lastChild;
     [PerWorldBindings] readonly attribute Node? previousSibling;
     [PerWorldBindings] readonly attribute Node? nextSibling;
 
     [CustomElementCallbacks] attribute DOMString? nodeValue;
     // FIXME: textContent should not have [TreatUndefinedAs=NullString].
     [TreatUndefinedAs=NullString, CustomElementCallbacks] attribute DOMString? textContent;
     [CustomElementCallbacks] void normalize();
 
     // FIXME: The deep argument should have a default value false.
@@ skipping 19 matching lines @@
     [CustomElementCallbacks, RaisesException] Node removeChild(Node child);
 
     // FIXME: namespaceURI and localName have been moved to Element and Attr.
     [MeasureAs=NodeNamespaceURI] readonly attribute DOMString? namespaceURI;
     [MeasureAs=NodeLocalName] readonly attribute DOMString? localName;
 
     // FIXME: isSameNode has been removed from the spec:
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=27424
     [MeasureAs=NodeIsSameNode] boolean isSameNode(Node? other);
 };