Implement MojoAudioRendererSink and use it in UtilityMojoMediaClient

media/mojo/interfaces/media_types.mojom

Index: media/mojo/interfaces/media_types.mojom
diff --git a/media/mojo/interfaces/media_types.mojom b/media/mojo/interfaces/media_types.mojom
index 0bd3b3a1ae43c70e9edd38a65828f0b5fbff79c8..e2c9b26203731b21b349cdea30692971b221cc51 100644
--- a/media/mojo/interfaces/media_types.mojom
+++ b/media/mojo/interfaces/media_types.mojom
@@ -157,6 +157,17 @@ struct AudioBuffer {
   array<uint8> data;
 };
 
+// This defines a mojo transport format for media::AudioBus.
+struct AudioBus {
+  // Number of channels.
+  int32 nb_channels;
+
+  // Number of frames.
+  int32 nb_frames;
+
+  array<float> data;
+};
+
 // This defines a mojo transport format for media::VideoFrame.
 struct VideoFrame {
   // Format of the frame.