Add mojo interface for audio rendering.

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";
+import "media/mojo/interfaces/media_types.mojom";
+import "url/mojo/origin.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();
+// On error, the message pipe is closed.
+// To close the stream, just close the message pipe.
+interface AudioOutput {
+  Start(AudioParameters params) =>
+       (handle<shared_buffer> shared_buffer,
+       handle socket_descriptor);
+  Play();
+  Pause();
+  SetVolume(double volume);
 };

[o1ka, 2017/01/25 15:15:21]

We want these two interfaces it live in separate mojoms, since they will be
hosted in separate processes.

 
-// This interface manages audio output streams.
-// It allows to create an AudioOutputStream.
-// TODO(rchtara): Add a method to request device authorization to this
-// 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,
-      AudioParameters params) =>
-      (int32 stream_id,
-       AudioOutputStream? stream,
-       handle<shared_buffer>? shared_buffer,
-       handle? socket_descriptor);
-};
+interface AudioOutputService {

[o1ka, 2017/01/25 15:15:21]

RendererAudioOutputService? Or some other more descriptive name?

+  // Used to request a device.
+  // An AudioOutputRequest may be supplied, in which case it will
+  // be bound to an AudioOutput implementation or closed (in case of an error).
+  // TODO better name.
+  RequestDeviceAuthorization(
+      // TODO(maxmorin): When input stream control is also switched to mojo,
+      // change session_id to be an int32_t in the code.
+      int64 session_id,
+      string device_id,
+      AudioOutput&? audio_output_request,
+      url.mojom.Origin origin) =>
+       (// TODO make this a struct?
+       OutputDeviceStatus state,
+       AudioParameters output_params,
+       string matched_device_id);
+};