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.mojom;
+
+import "media/mojo/interfaces/audio_parameters.mojom";
+
+// This interface handles audio output stream operations.
+// It allows to close a stream.
+// TODO(rchtara): Add methods that allow the interaction with audio output
+// streams: Play, Pause and SetVolume to this interface.
+// See crbug.com/606707 for more details.
+interface AudioOutputStream {
+  Close();
+};
+
+// This interface manages audio output streams.
+// It allows to create an AudioOutputStream.
+// TODO(rchtara): Add method to request a device authorization to this

[Henrik Grunell, 2016/05/12 10:34:37]

Nit: "request device authorization"

[rchtara, 2016/05/13 12:00:09]

Done.

+// interface.
+// See crbug.com/606707 for more details.
+interface AudioOutput {
+  // TODO(rchtara): Remove |stream_id| from AudioOutput::CreateStream when all
+  // the stream operations are mojofied.
+  CreateStream(
+      int32 stream_id,
+      media.interfaces.AudioParameters params) =>
+      (int32 stream_id,
+       AudioOutputStream? stream,
+       handle<shared_buffer>? shared_buffer,
+       handle? socket_descriptor);
+   // Used to close streams which are just authorized but not created yet.
+   CloseStream(int32 stream_id);

[Henrik Grunell, 2016/05/12 10:34:37]

I suppose there should only be one way of closing the stream? Here or in
AudioOutputStream. If this really will be needed for the Authorization case,
let's add it when authorization is added. I.e. remove CloseStream for now.

[rchtara, 2016/05/13 12:00:09]

After a discussion with grunell: we decided to keep temporally the ipc for
closing the streams that are authorized and not created yet : so we don't have
to add the AudioOutpu.CloseStream.

These streams will be closed using AudioOutputStream.Close later when
RequestDeviceAuthorization will be mojofied  

+};