Use 'field' syntax in dart:dom interfaces.

client/dom/generated/src/interface/AudioBuffer.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.
 
 interface AudioBuffer {
 
-  num get duration();
+  final num duration;
 
-  num get gain();
+  num gain;
 
-  void set gain(num value);
+  final int length;
 
-  int get length();
+  final int numberOfChannels;
 
-  int get numberOfChannels();
-
-  num get sampleRate();
+  final num sampleRate;
 
   Float32Array getChannelData(int channelIndex);
 }