Change ForwardErrorCorrection class to accept one received packet at a time.

modules/rtp_rtcp/source/forward_error_correction.h

Index: modules/rtp_rtcp/source/forward_error_correction.h
diff --git a/modules/rtp_rtcp/source/forward_error_correction.h b/modules/rtp_rtcp/source/forward_error_correction.h
index f821f6f26d45d9abce8da50311a05bc0ca10e91f..97acb393f35a1265e93ba21609cb30b9c1152cbc 100644
--- a/modules/rtp_rtcp/source/forward_error_correction.h
+++ b/modules/rtp_rtcp/source/forward_error_correction.h
@@ -75,9 +75,10 @@ class ForwardErrorCorrection {
     uint16_t seq_num;
   };
 
-  // The received list parameter of DecodeFec() references structs of this type.
+  // Used for the input to DecodeFec().
   //
-  // TODO(holmer): Refactor into a proper class.
+  // TODO(nisse): Delete class, instead passing |is_fec| and |pkt| as separate
+  // arguments.
   class ReceivedPacket : public SortablePacket {
    public:
     ReceivedPacket();
@@ -141,7 +142,6 @@ class ForwardErrorCorrection {
   };
 
   using PacketList = std::list<std::unique_ptr<Packet>>;
-  using ReceivedPacketList = std::list<std::unique_ptr<ReceivedPacket>>;
   using RecoveredPacketList = std::list<std::unique_ptr<RecoveredPacket>>;
   using ReceivedFecPacketList = std::list<std::unique_ptr<ReceivedFecPacket>>;
 
@@ -218,10 +218,8 @@ class ForwardErrorCorrection {
   //                            list will be valid until the next call to
   //                            DecodeFec().
   //
-  // Returns 0 on success, -1 on failure.
-  //
-  int DecodeFec(ReceivedPacketList* received_packets,
-                RecoveredPacketList* recovered_packets);
+  void DecodeFec(const ReceivedPacket& received_packet,
+                 RecoveredPacketList* recovered_packets);
 
   // Get the number of generated FEC packets, given the number of media packets
   // and the protection factor.
@@ -266,14 +264,14 @@ class ForwardErrorCorrection {
                           uint32_t media_ssrc,
                           uint16_t seq_num_base);
 
-  // Inserts the |received_packets| into the internal received FEC packet list
+  // Inserts the |received_packet| into the internal received FEC packet list
   // or into |recovered_packets|.
-  void InsertPackets(ReceivedPacketList* received_packets,
-                     RecoveredPacketList* recovered_packets);
+  void InsertPacket(const ReceivedPacket& received_packet,
+                    RecoveredPacketList* recovered_packets);
 
   // Inserts the |received_packet| into |recovered_packets|. Deletes duplicates.
   void InsertMediaPacket(RecoveredPacketList* recovered_packets,
-                         ReceivedPacket* received_packet);
+                         const ReceivedPacket& received_packet);
 
   // Assigns pointers to the recovered packet from all FEC packets which cover
   // it.
@@ -284,7 +282,7 @@ class ForwardErrorCorrection {
 
   // Insert |received_packet| into internal FEC list. Deletes duplicates.
   void InsertFecPacket(const RecoveredPacketList& recovered_packets,
-                       ReceivedPacket* received_packet);
+                       const ReceivedPacket& received_packet);
 
   // Assigns pointers to already recovered packets covered by |fec_packet|.
   static void AssignRecoveredPackets(