Cast:Transport: Dividing A/V Initialization pipeline

media/cast/transport/cast_transport_config.h

Index: media/cast/transport/cast_transport_config.h
diff --git a/media/cast/transport/cast_transport_config.h b/media/cast/transport/cast_transport_config.h
index 90d039cb34fc9203ec71a93378d3d9bf28078e8d..211dc4e9b8d56865760ed8374787585fdfadc1e3 100644
--- a/media/cast/transport/cast_transport_config.h
+++ b/media/cast/transport/cast_transport_config.h
@@ -43,29 +43,32 @@ struct RtpConfig {
   int payload_type;
 };
 
-struct CastTransportConfig {
-  CastTransportConfig();
-  ~CastTransportConfig();
+struct CastTransportBaseConfig {
+  CastTransportBaseConfig();
+  ~CastTransportBaseConfig();
 
-  // Transport: Local receiver.
-  net::IPEndPoint receiver_endpoint;
-  net::IPEndPoint local_endpoint;
-
-  uint32 audio_ssrc;
-  uint32 video_ssrc;
+  uint32 ssrc;

[Ami GONE FROM CHROMIUM, 2014/02/25 00:22:17]

is there any reason to support mutable config objects?  
It would be much cleaner to make all the members const and set them in the ctor,
which would also handily avoid the need to initialize members to arbitrary
defaults.  E.g. why does it make sense to set an audio codec to kOpus by
default?

[mikhal1, 2014/02/25 18:07:02]

The rational is that most of the use cases are the same. It also makes it easier
for testing (but that might be not a good enough reason).
On 2014/02/25 00:22:17, Ami Fischman wrote:

+  RtpConfig rtp_config;
+  std::string aes_key;      // Binary string of size kAesKeySize.
+  std::string aes_iv_mask;  // Binary string of size kAesBlockSize.
+};
 
-  VideoCodec video_codec;
-  AudioCodec audio_codec;
+struct CastTransportAudioConfig {
+  CastTransportAudioConfig();
+  ~CastTransportAudioConfig();
 
-  // RTP.
-  RtpConfig audio_rtp_config;
-  RtpConfig video_rtp_config;
+  CastTransportBaseConfig base;
+  AudioCodec codec;
+  int frequency;
+  int channels;
+};
 
-  int audio_frequency;
-  int audio_channels;
+struct CastTransportVideoConfig {
+  CastTransportVideoConfig();
+  ~CastTransportVideoConfig();
 
-  std::string aes_key;      // Binary string of size kAesKeySize.
-  std::string aes_iv_mask;  // Binary string of size kAesBlockSize.
+  CastTransportBaseConfig base;
+  VideoCodec codec;
 };
 
 struct EncodedVideoFrame {