Add FlexFEC header formatters. (pt. 5)

webrtc/modules/rtp_rtcp/source/ulpfec_header_reader_writer.h

 /*
  *  Copyright (c) 2016 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.
  */
 
@@ skipping 37 matching lines @@
  public:
   UlpfecHeaderWriter();
   ~UlpfecHeaderWriter() override;
 
   size_t MinPacketMaskSize(const uint8_t* packet_mask,
                            size_t packet_mask_size) const override;
 
   size_t FecHeaderSize(size_t packet_mask_row_size) const override;
 
   void FinalizeFecHeader(
+      uint32_t media_ssrc,  // Unused by ULPFEC.
       uint16_t seq_num_base,
       const uint8_t* packet_mask,
       size_t packet_mask_size,
       ForwardErrorCorrection::Packet* fec_packet) const override;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_ULPFEC_HEADER_READER_WRITER_H_