Don't put private members in dart:html interfaces.

client/html/src/shared_FactoryProviders.dart

 // 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.
 
 class _TextFactoryProvider {
 
-  factory Text(String data) => document._createTextNode(data);
+  factory Text(String data) {
+    final _DocumentImpl doc = document;
+    return doc._createTextNode(data);
+  }
 }
 
 class _EventFactoryProvider {
   factory Event(String type, [bool canBubble = true,
       bool cancelable = true]) {
-    _EventImpl e = document._createEvent("Event");
+    final _DocumentImpl doc = document;
+    final _EventImpl e = doc._createEvent("Event");
     e._initEvent(type, canBubble, cancelable);
     return e;
   }
 }
 
 class _MouseEventFactoryProvider {
   factory MouseEvent(String type, Window view, int detail,
       int screenX, int screenY, int clientX, int clientY, int button,
       [bool canBubble = true, bool cancelable = true, bool ctrlKey = false,
       bool altKey = false, bool shiftKey = false, bool metaKey = false,
       EventTarget relatedTarget = null]) {
-    final e = document._createEvent("MouseEvent");
+    final _DocumentImpl doc = document;
+    final e = doc._createEvent("MouseEvent");
     e._initMouseEvent(type, canBubble, cancelable, view, detail,
         screenX, screenY, clientX, clientY, ctrlKey, altKey, shiftKey, metaKey,
         button, relatedTarget);
     return e;
   }
 }
 
 class _CSSStyleDeclarationFactoryProvider {
   factory CSSStyleDeclaration.css(String css) {
     var style = new Element.tag('div').style;
@@ skipping 32 matching lines @@
     // 4) Detatch the created element from its dummy parent.
     String parentTag = 'div';
     String tag;
     final match = _START_TAG_REGEXP.firstMatch(html);
     if (match !== null) {
       tag = match.group(1).toLowerCase();
       if (_CUSTOM_PARENT_TAG_MAP.containsKey(tag)) {
         parentTag = _CUSTOM_PARENT_TAG_MAP[tag];
       }
     }
-    // TODO(jacobr): make type dom.HTMLElement when dartium allows it.
-    _ElementImpl temp = document._createElement(parentTag);
+    final _ElementImpl temp = new Element.tag(parentTag);
     temp.innerHTML = html;
 
     Element element;
     if (temp.elements.length == 1) {
       element = temp.elements.first;
     } else if (parentTag == 'html' && temp.elements.length == 2) {
       // Work around for edge case in WebKit and possibly other browsers where
       // both body and head elements are created even though the inner html
       // only contains a head or body element.
       element = temp.elements[tag == 'head' ? 0 : 1];
     } else {
       throw new IllegalArgumentException('HTML had ${temp.elements.length} ' +
           'top level elements but 1 expected');
     }
     element.remove();
     return element;
   }
 
   /** @domName Document.createElement */
   factory Element.tag(String tag) {
-    return document._createElement(tag);
+    final _DocumentImpl doc = document;
+    return doc._createElement(tag);
   }
 }