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

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

Index: client/dom/generated/src/frog/AudioBufferSourceNode.dart
diff --git a/client/dom/generated/src/frog/AudioBufferSourceNode.dart b/client/dom/generated/src/frog/AudioBufferSourceNode.dart
index 91826a8a4ea944a61d8054bbf28460e16391b820..a00bd285097d6f852de87dc4205beba2ce6104a5 100644
--- a/client/dom/generated/src/frog/AudioBufferSourceNode.dart
+++ b/client/dom/generated/src/frog/AudioBufferSourceNode.dart
@@ -1,21 +1,15 @@
 
 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;