Add audio_device_id in mojo media ServiceFactory CreateRenderer api.

media/mojo/interfaces/service_factory.mojom

Index: media/mojo/interfaces/service_factory.mojom
diff --git a/media/mojo/interfaces/service_factory.mojom b/media/mojo/interfaces/service_factory.mojom
index b55e284c226d2b321e52f0344897742237d34bd4..611417f68accc7bc4c4d6e1050282c1325fdf39f 100644
--- a/media/mojo/interfaces/service_factory.mojom
+++ b/media/mojo/interfaces/service_factory.mojom
@@ -19,7 +19,11 @@ interface ServiceFactory {
   CreateVideoDecoder(VideoDecoder& video_decoder);
 
   // Creates a Renderer service.
-  CreateRenderer(Renderer& renderer);
+  // Audio stream will be played on device_id, which is defined in
+  // media/audio/audio_device_description.h. If audio_device_id
+  // is null, kDefaultDeviceId will be used. 
+  CreateRenderer(Renderer& renderer,
+                 string? audio_device_id);

[alokp, 2016/06/01 00:06:14]

Since kDefaultDeviceId is already defined, may be it is better to make the
device-id as required parameter?

[tianyuwang1, 2016/06/02 03:32:32]

xhwang@ suggested that we should make this audio_device_id optional instead of
required.  so that when it's not set we can use the default device.  This is
what other places that use device_id is doing too.  If device_id is empty then
use default device.

 
   // Creates a ContentDecryptionModule service.
   CreateCdm(ContentDecryptionModule& cdm);