Making all DOM types abstract and removing superfluous Dartium constructors.

tools/dom/templates/html/dart2js/impl_KeyboardEvent.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.
 
 
-$(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
+$(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   factory $CLASSNAME(String type,
       {Window view, bool canBubble: true, bool cancelable: true,
       String keyIdentifier: "", int keyLocation: 1, bool ctrlKey: false,
       bool altKey: false, bool shiftKey: false, bool metaKey: false,
       bool altGraphKey: false}) {
     if (view == null) {
       view = window;
     }
     final e = document.$dom_createEvent("KeyboardEvent");
@@ skipping 22 matching lines @@
     }
   }
 
   @DomName('KeyboardEvent.keyCode')
   int get keyCode => $dom_keyCode;
 
   @DomName('KeyboardEvent.charCode')
   int get charCode => $dom_charCode;
 $!MEMBERS
 }