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

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

 
 class _AudioContextJs extends _DOMTypeJs implements AudioContext native "*AudioContext" {
   AudioContext() native;
 
 
-  num get currentTime() native "return this.currentTime;";
+  final num currentTime;
 
-  _AudioDestinationNodeJs get destination() native "return this.destination;";
+  final _AudioDestinationNodeJs destination;
 
-  _AudioListenerJs get listener() native "return this.listener;";
+  final _AudioListenerJs listener;
 
-  EventListener get oncomplete() native "return this.oncomplete;";
+  EventListener oncomplete;
 
-  void set oncomplete(EventListener value) native "this.oncomplete = value;";
-
-  num get sampleRate() native "return this.sampleRate;";
+  final num sampleRate;
 
   _RealtimeAnalyserNodeJs createAnalyser() native;
 
   _BiquadFilterNodeJs createBiquadFilter() native;
 
   _AudioBufferJs createBuffer(var buffer_OR_numberOfChannels, var mixToMono_OR_numberOfFrames, [num sampleRate = null]) native;
 
   _AudioBufferSourceNodeJs createBufferSource() native;
 
   _AudioChannelMergerJs createChannelMerger() native;
@@ skipping 17 matching lines @@
   _MediaElementAudioSourceNodeJs createMediaElementSource(_HTMLMediaElementJs mediaElement) native;
 
   _AudioPannerNodeJs createPanner() native;
 
   _WaveShaperNodeJs createWaveShaper() native;
 
   void decodeAudioData(_ArrayBufferJs audioData, AudioBufferCallback successCallback, [AudioBufferCallback errorCallback = null]) native;
 
   void startRendering() native;
 }