Get rid of a lot of () for getters.

lib/html/src/ErrorEventWrappingImplementation.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.
 
 class ErrorEventWrappingImplementation extends EventWrappingImplementation implements ErrorEvent {
   ErrorEventWrappingImplementation._wrap(ptr) : super._wrap(ptr);
 
   factory ErrorEventWrappingImplementation(String type, String message,
       String filename, int lineNo, [bool canBubble = true,
       bool cancelable = true]) {
     final e = dom.document.createEvent("ErrorEvent");
     e.initErrorEvent(type, canBubble, cancelable, message, filename, lineNo);
     return LevelDom.wrapErrorEvent(e);
   }
 
-  String get filename() => _ptr.filename;
+  String get filename => _ptr.filename;
 
-  int get lineno() => _ptr.lineno;
+  int get lineno => _ptr.lineno;
 
-  String get message() => _ptr.message;
+  String get message => _ptr.message;
 }