Getting html_dart2js and html_dartium a bit more in sync.

tools/dom/templates/html/impl/impl_WheelEvent.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.
 
 part of $LIBRARYNAME;
 
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   factory WheelEvent(String type,
       {Window view, int deltaX: 0, int deltaY: 0,
@@ skipping 212 matching lines @@
 $else
   /**
    * The amount that is expected to scroll horizontally, in units determined by
    * [deltaMode].
    *
    * See also:
    *
    * * [WheelEvent.deltaX](http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html#events-WheelEvent-deltaX) from the W3C.
    */
   @DomName('WheelEvent.deltaX')
-  num get deltaX => -$dom_wheelDeltaX;
+  num get deltaX => -_wheelDeltaX;
 
   /**
    * The amount that is expected to scroll vertically, in units determined by
    * [deltaMode].
    *
    * See also:
    *
    * * [WheelEvent.deltaY](http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html#events-WheelEvent-deltaY) from the W3C.
    */
   @DomName('WheelEvent.deltaY')
-  num get deltaY => -$dom_wheelDeltaY;
+  num get deltaY => -_wheelDeltaY;
 $endif
 }