[Cast] Cleanup: Remove TransportXXXXXSender, an unnecessary layer of indirection.

media/cast/transport/cast_transport_sender_impl.h

Index: media/cast/transport/cast_transport_sender_impl.h
diff --git a/media/cast/transport/cast_transport_sender_impl.h b/media/cast/transport/cast_transport_sender_impl.h
index 91b03c52bedde6ea99edd95be127dc43f407c3e4..0f440fb5076a01725e1e03dc2d084ecaade3e11c 100644
--- a/media/cast/transport/cast_transport_sender_impl.h
+++ b/media/cast/transport/cast_transport_sender_impl.h
@@ -17,8 +17,8 @@
 #include "media/cast/transport/cast_transport_sender.h"
 #include "media/cast/transport/pacing/paced_sender.h"
 #include "media/cast/transport/rtcp/rtcp_builder.h"
-#include "media/cast/transport/transport_audio_sender.h"
-#include "media/cast/transport/transport_video_sender.h"
+#include "media/cast/transport/rtp_sender/rtp_sender.h"
+#include "media/cast/transport/utility/transport_encryption_handler.h"
 
 namespace media {
 namespace cast {
@@ -82,8 +82,15 @@ class CastTransportSenderImpl : public CastTransportSender {
   LoggingImpl logging_;
   PacedSender pacer_;
   RtcpBuilder rtcp_builder_;
-  scoped_ptr<TransportAudioSender> audio_sender_;
-  scoped_ptr<TransportVideoSender> video_sender_;
+  scoped_ptr<RtpSender> audio_sender_;
+  scoped_ptr<RtpSender> video_sender_;
+
+  // Encrypts data in EncodedFrames before they are sent.  Note that it's
+  // important for the encryption to happen here, in code that would execute in
+  // the main browser process, for security reasons.  This helps to mitigate
+  // the damage that could be caused by a compromised renderer process.
+  TransportEncryptionHandler audio_encryptor_;
+  TransportEncryptionHandler video_encryptor_;
 
   // This is non-null iff |raw_events_callback_| is non-null.
   scoped_ptr<SimpleEventSubscriber> event_subscriber_;