Use fields in hidden native DOM classes instead of getters/setters.

client/dom/generated/src/frog/AudioBufferSourceNode.dart

 
 class _AudioBufferSourceNodeJs extends _AudioSourceNodeJs implements AudioBufferSourceNode native "*AudioBufferSourceNode" {
 
-  _AudioBufferJs get buffer() native "return this.buffer;";
+  _AudioBufferJs buffer;
 
-  void set buffer(_AudioBufferJs value) native "this.buffer = value;";
+  final _AudioGainJs gain;
 
-  _AudioGainJs get gain() native "return this.gain;";
+  bool loop;
 
-  bool get loop() native "return this.loop;";
+  bool looping;
 
-  void set loop(bool value) native "this.loop = value;";
-
-  bool get looping() native "return this.looping;";
-
-  void set looping(bool value) native "this.looping = value;";
-
-  _AudioParamJs get playbackRate() native "return this.playbackRate;";
+  final _AudioParamJs playbackRate;
 
   void noteGrainOn(num when, num grainOffset, num grainDuration) native;
 
   void noteOff(num when) native;
 
   void noteOn(num when) native;
 }