Remove NPObject from generated dart:html for Dartium.

tools/dom/src/native_DOMImplementation.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.
 
 part of html;
 
 class _ConsoleVariables {
   Map<String, Object> _data = new Map<String, Object>();
 
   /**
@@ skipping 280 matching lines @@
     }
     _register(document, tag, type, extendsTagName);
   }
 
   static void _register(Document document, String tag, Type customType,
       String extendsTagName) native "Utils_register";
 
   static Element createElement(Document document, String tagName) native "Utils_createElement";
 }
 
-class _NPObject extends NativeFieldWrapperClass1 {
-  _NPObject.internal();
-  static _NPObject retrieve(String key) native "NPObject_retrieve";
-  property(String propertyName) native "NPObject_property";
-  invoke(String methodName, [List args = null]) native "NPObject_invoke";
-}
-
 class _DOMWindowCrossFrame extends NativeFieldWrapperClass1 implements
     WindowBase {
   _DOMWindowCrossFrame.internal();
 
   // Fields.
   HistoryBase get history native "Window_history_cross_frame_Getter";
   LocationBase get location native "Window_location_cross_frame_Getter";
   bool get closed native "Window_closed_Getter";
   int get length native "Window_length_Getter";
   WindowBase get opener native "Window_opener_Getter";
@@ skipping 192 matching lines @@
   _send(msg) {
     _sendToHelperIsolate(msg, _sendPort);
   }
 
   bool get isActive => _isActive;
 }
 
 get _pureIsolateTimerFactoryClosure =>
     ((int milliSeconds, void callback(Timer time), bool repeating) =>
         new _PureIsolateTimer(milliSeconds, callback, repeating));