Get rid of a lot of () for getters.

lib/html/src/MutationEvent.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.
 
 interface MutationEvent extends Event default MutationEventWrappingImplementation {
 
   MutationEvent(String type, Node relatedNode, String prevValue,
       String newValue, String attrName, int attrChange, [bool canBubble,
       bool cancelable]);
 
   static const int ADDITION = 2;
 
   static const int MODIFICATION = 1;
 
   static const int REMOVAL = 3;
 
-  int get attrChange();
+  int get attrChange;
 
-  String get attrName();
+  String get attrName;
 
-  String get newValue();
+  String get newValue;
 
-  String get prevValue();
+  String get prevValue;
 
-  Node get relatedNode();
+  Node get relatedNode;
 }