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

media/mojo/interfaces/audio_output.mojom

Index: media/mojo/interfaces/audio_output.mojom
diff --git a/media/mojo/interfaces/audio_output.mojom b/media/mojo/interfaces/audio_output.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..684661e794793488f655dd067e612f1adc79fd66
--- /dev/null
+++ b/media/mojo/interfaces/audio_output.mojom
@@ -0,0 +1,22 @@
+// 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 content.mojom;

[xhwang, 2016/04/26 22:54:42]

This file is in media/mojo where we use media.interfaces as the module. We do
have a plan to switch to media.mojom in the future, but for now it'd be nice to
be consistent with existing interfaces.

[rchtara, 2016/04/29 12:54:46]

Done.

+
+import "media/mojo/interfaces/media_types.mojom";
+
+interface AudioOutputStream {

[xhwang, 2016/04/26 22:54:42]

Please provide some comments about what this is for. An interface with just a
Close() call seems odd.

[rchtara, 2016/04/29 12:54:46]

Done.

+  Close();
+};
+
+interface AudioOutput {

[xhwang, 2016/04/26 22:54:42]

ditto for comments.

[rchtara, 2016/04/29 12:54:46]

Done.

+  CreateStream(
+      int32 stream_id,
+      int32 render_frame_id,

[xhwang, 2016/04/26 22:54:42]

Hmm, media should know nothing about content (e.g. render_frame_id). If this is
really necessary, then this interface should be defined in content instead in
media.

[rchtara, 2016/04/29 12:54:46]

At the beginning, I tried to define the interface in content, but I failed and I
got a presubmit error: as the interface is going to be used in
audio_output_controller.h which is in media and we cannot include things defined
in content in media.

+      media.interfaces.AudioOutputStreamParameters params) =>
+      (int32 stream_id,
+       AudioOutputStream? stream,
+       handle<shared_buffer>? shared_buffer,
+       handle? socket_descriptor);
+};