Replaced Element.append with Node.appendChild

tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate

 // Copyright (c) 2011, 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.
 
 part of $LIBRARYNAME;
 
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   factory $CLASSNAME() => _$(CLASSNAME)FactoryProvider.createDocumentFragment();
 
   factory $CLASSNAME.html(String html) =>
@@ skipping 24 matching lines @@
     children.addAll(copy);
   }
 
   Element query(String selectors) => $dom_querySelector(selectors);
 
   List<Element> queryAll(String selectors) =>
     new _FrozenElementList._wrap($dom_querySelectorAll(selectors));
 
   String get innerHtml {
     final e = new Element.tag("div");
-    e.nodes.add(this.clone(true));
+    e.append(this.clone(true));
     return e.innerHtml;
   }
 
   // TODO(nweiz): Do we want to support some variant of innerHtml for XML and/or
   // SVG strings?
   void set innerHtml(String value) {
     this.nodes.clear();
 
     final e = new Element.tag("div");
     e.innerHtml = value;
 
     // Copy list first since we don't want liveness during iteration.
     List nodes = new List.from(e.nodes);
     this.nodes.addAll(nodes);
   }
 
   /**
-   * Adds the specified element after the last child of this
-   * document fragment.
-   */
-  void append(Element element) {
-    this.children.add(element);
-  }
-
-  /**
    * Adds the specified text as a text node after the last child of this
    * document fragment.
    */
   void appendText(String text) {
-    this.nodes.add(new Text(text));
+    this.append(new Text(text));
   }
 
 
   /**
    * Parses the specified text as HTML and adds the resulting node after the
    * last child of this document fragment.
    */
   void appendHtml(String text) {
-    this.nodes.add(new DocumentFragment.html(text));
+    this.append(new DocumentFragment.html(text));
   }
 
 $!MEMBERS
 }