Turn on webaudio for JS backends.

client/dom/generated/src/wrapping/_AudioGainWrappingImplementation.dart

Index: client/dom/generated/src/wrapping/_AudioGainWrappingImplementation.dart
diff --git a/client/dom/generated/src/wrapping/_AudioGainWrappingImplementation.dart b/client/dom/generated/src/wrapping/_AudioGainWrappingImplementation.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5425d0c794daf03310c6e2f70e622f7fe9e628b9
--- /dev/null
+++ b/client/dom/generated/src/wrapping/_AudioGainWrappingImplementation.dart
@@ -0,0 +1,15 @@
+// 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.
+
+class _AudioGainWrappingImplementation extends _AudioParamWrappingImplementation implements AudioGain {
+  _AudioGainWrappingImplementation() : super() {}
+
+  static create__AudioGainWrappingImplementation() native {
+    return new _AudioGainWrappingImplementation();
+  }
+
+  String get typeName() { return "AudioGain"; }
+}