Convert DOM and HTML frog to dart2js.

lib/dom/templates/html/impl/impl_Node.darttemplate

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Lazy implementation of the child nodes of an element that does not request
  * the actual child nodes of an element until strictly necessary greatly
  * improving performance for the typical cases where it is not required.
  */
 class _ChildNodeListLazy implements NodeList {
   final _NodeImpl _this;
 
   _ChildNodeListLazy(this._this);
 
 
-$if FROG
+$if DART2JS
   _NodeImpl get first() native "return this._this.firstChild;";
   _NodeImpl last() native "return this._this.lastChild;";
 $else
   _NodeImpl get first() => _this.$dom_firstChild;
   _NodeImpl last() => _this.$dom_lastChild;
 $endif
 
   void add(_NodeImpl value) {
     _this.$dom_appendChild(value);
   }
@@ skipping 110 matching lines @@
       final _NodeImpl parent = this.parent;
       parent.$dom_replaceChild(otherNode, this);
     } catch(var e) {
       
     };
     return this;
   }
 
 $!MEMBERS
 }