Turn on webaudio for JS backends.

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
new file mode 100644
index 0000000000000000000000000000000000000000..66f1e2b2741761e66290f6b6633aed9438658e6f
--- /dev/null
+++ b/client/dom/generated/src/frog/AudioBufferSourceNode.dart
@@ -0,0 +1,19 @@
+
+class AudioBufferSourceNode extends AudioSourceNode native "*AudioBufferSourceNode" {
+
+  AudioBuffer buffer;
+
+  AudioGain gain;
+
+  bool loop;
+
+  bool looping;
+
+  AudioParam playbackRate;
+
+  void noteGrainOn(num when, num grainOffset, num grainDuration) native;
+
+  void noteOff(num when) native;
+
+  void noteOn(num when) native;
+}