Reland of Only compare sequence numbers from the same SSRC in ForwardErrorCorrection.

webrtc/modules/rtp_rtcp/source/ulpfec_receiver_impl.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_MODULES_RTP_RTCP_SOURCE_ULPFEC_RECEIVER_IMPL_H_
 #define WEBRTC_MODULES_RTP_RTCP_SOURCE_ULPFEC_RECEIVER_IMPL_H_
 
 #include <memory>
 
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/rtp_rtcp/include/ulpfec_receiver.h"
 #include "webrtc/modules/rtp_rtcp/source/forward_error_correction.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 class UlpfecReceiverImpl : public UlpfecReceiver {
  public:
-  explicit UlpfecReceiverImpl(RecoveredPacketReceiver* callback);
+  explicit UlpfecReceiverImpl(uint32_t ssrc, RecoveredPacketReceiver* callback);
   virtual ~UlpfecReceiverImpl();
 
   int32_t AddReceivedRedPacket(const RTPHeader& rtp_header,
                                const uint8_t* incoming_rtp_packet,
                                size_t packet_length,
                                uint8_t ulpfec_payload_type) override;
 
   int32_t ProcessReceivedFec() override;
 
   FecPacketCounter GetPacketCounter() const override;
 
  private:
+  const uint32_t ssrc_;
+
   rtc::CriticalSection crit_sect_;
   RecoveredPacketReceiver* recovered_packet_callback_;
   std::unique_ptr<ForwardErrorCorrection> fec_;
   // TODO(holmer): In the current version |received_packets_| is never more
   // than one packet, since we process FEC every time a new packet
   // arrives. We should remove the list.
   ForwardErrorCorrection::ReceivedPacketList received_packets_;
   ForwardErrorCorrection::RecoveredPacketList recovered_packets_;
   FecPacketCounter packet_counter_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_ULPFEC_RECEIVER_IMPL_H_