Set the preferred DSCP value for Rtp data channel to be DSCP_AF41.

webrtc/media/base/rtpdataengine.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_MEDIA_BASE_RTPDATAENGINE_H_
 #define WEBRTC_MEDIA_BASE_RTPDATAENGINE_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "webrtc/media/base/mediachannel.h"
 #include "webrtc/media/base/mediaconstants.h"
 #include "webrtc/media/base/mediaengine.h"
 
 namespace cricket {
 
 struct DataCodec;
 
 class RtpDataEngine : public DataEngineInterface {
  public:
   RtpDataEngine();
 
-  virtual DataMediaChannel* CreateChannel(DataChannelType data_channel_type);
+  virtual DataMediaChannel* CreateChannel(DataChannelType data_channel_type,
+                                          const MediaConfig& config);
 
   virtual const std::vector<DataCodec>& data_codecs() {
     return data_codecs_;
   }
 
  private:
   std::vector<DataCodec> data_codecs_;
 };
 
 // Keep track of sequence number and timestamp of an RTP stream.  The
@@ skipping 13 matching lines @@
   void Tick(double now, int* seq_num, uint32_t* timestamp);
 
  private:
   int clockrate_;
   uint16_t last_seq_num_;
   uint32_t timestamp_offset_;
 };
 
 class RtpDataMediaChannel : public DataMediaChannel {
  public:
-  RtpDataMediaChannel();
+  RtpDataMediaChannel(const MediaConfig& config);
   virtual ~RtpDataMediaChannel();
 
   virtual bool SetSendParameters(const DataSendParameters& params);
   virtual bool SetRecvParameters(const DataRecvParameters& params);
   virtual bool AddSendStream(const StreamParams& sp);
   virtual bool RemoveSendStream(uint32_t ssrc);
   virtual bool AddRecvStream(const StreamParams& sp);
   virtual bool RemoveRecvStream(uint32_t ssrc);
   virtual bool SetSend(bool send) {
     sending_ = send;
     return true;
   }
   virtual bool SetReceive(bool receive) {
     receiving_ = receive;
     return true;
   }
   virtual void OnPacketReceived(rtc::CopyOnWriteBuffer* packet,
                                 const rtc::PacketTime& packet_time);
   virtual void OnRtcpReceived(rtc::CopyOnWriteBuffer* packet,
                               const rtc::PacketTime& packet_time) {}
   virtual void OnReadyToSend(bool ready) {}
   virtual void OnTransportOverheadChanged(int transport_overhead_per_packet) {}
   virtual bool SendData(
     const SendDataParams& params,
     const rtc::CopyOnWriteBuffer& payload,
     SendDataResult* result);
+  virtual rtc::DiffServCodePoint PreferredDscp() const;
 
  private:
   void Construct();
   bool SetMaxSendBandwidth(int bps);
   bool SetSendCodecs(const std::vector<DataCodec>& codecs);
   bool SetRecvCodecs(const std::vector<DataCodec>& codecs);
 
   bool sending_;
   bool receiving_;
   std::vector<DataCodec> send_codecs_;
   std::vector<DataCodec> recv_codecs_;
   std::vector<StreamParams> send_streams_;
   std::vector<StreamParams> recv_streams_;
   std::map<uint32_t, RtpClock*> rtp_clock_by_send_ssrc_;
   std::unique_ptr<rtc::RateLimiter> send_limiter_;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_BASE_RTPDATAENGINE_H_