Mojo interfaces needed for switching audio rendering stream creation and closing from IPC to Mojo

media/mojo/interfaces/audio_output.mojom

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module media.interfaces;
+
+import "media/mojo/interfaces/media_types.mojom";
+
+interface AudioOutputStream {
+  Close();
+};
+
+interface AudioOutput {
+  CreateStream(
+      int32 stream_id,
+      int32 render_frame_id,
+      AudioOutputStreamParameters params) =>
+      (int32 stream_id,
+       AudioOutputStream? stream,
+       handle<shared_buffer>? shared_buffer,
+       handle? socket_descriptor);
+};