Cast:Adding cast_transport_config and cleaning up

media/cast/transport/rtp_sender/rtp_sender.h

Index: media/cast/transport/rtp_sender/rtp_sender.h
diff --git a/media/cast/transport/rtp_sender/rtp_sender.h b/media/cast/transport/rtp_sender/rtp_sender.h
index cb2c12f651b5c93d0d731a666538969dc837561f..cc704a1bbe4219d0685c969440d927b81bf67187 100644
--- a/media/cast/transport/rtp_sender/rtp_sender.h
+++ b/media/cast/transport/rtp_sender/rtp_sender.h
@@ -31,7 +31,7 @@ class PacedPacketSender;
 // acknowledged by the remote peer or timed out.
 class RtpSender {
  public:
-  RtpSender(scoped_refptr<CastEnvironment> cast_environment,
+  RtpSender(base::TickClock* clock,
             const AudioSenderConfig* audio_config,
             const VideoSenderConfig* video_config,
             PacedPacketSender* transport);
@@ -53,7 +53,6 @@ class RtpSender {
  private:
   void UpdateSequenceNumber(std::vector<uint8>* packet);
 
-  scoped_refptr<CastEnvironment> cast_environment_;
   RtpPacketizerConfig config_;
   scoped_ptr<RtpPacketizer> packetizer_;
   scoped_ptr<PacketStorage> storage_;