Remove support for attribute event listeners.

client/dom/generated/src/wrapping/_SharedWorkercontextWrappingImplementation.dart

 // 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.
 
 // WARNING: Do not edit - generated code.
 
 class _SharedWorkercontextWrappingImplementation extends _WorkerContextWrappingImplementation implements SharedWorkercontext {
   _SharedWorkercontextWrappingImplementation() : super() {}
 
   static create__SharedWorkercontextWrappingImplementation() native {
     return new _SharedWorkercontextWrappingImplementation();
   }
 
   String get name() { return _get_name(this); }
   static String _get_name(var _this) native;
 
-  EventListener get onconnect() { return _get_onconnect(this); }
-  static EventListener _get_onconnect(var _this) native;
-
-  void set onconnect(EventListener value) { _set_onconnect(this, value); }
-  static void _set_onconnect(var _this, EventListener value) native;
-
   String get typeName() { return "SharedWorkercontext"; }
 }