Fix RTPPayloadRegistry to correctly restore RTX, if a valid mapping exists.

webrtc/modules/rtp_rtcp/interface/rtp_payload_registry.h

Index: webrtc/modules/rtp_rtcp/interface/rtp_payload_registry.h
diff --git a/webrtc/modules/rtp_rtcp/interface/rtp_payload_registry.h b/webrtc/modules/rtp_rtcp/interface/rtp_payload_registry.h
index bcafdfb7f600f81a395fe2f88cd4b95f4e1c5e5f..a60a6c5e73c0e54feb07a7affb0bb98dd3564d6b 100644
--- a/webrtc/modules/rtp_rtcp/interface/rtp_payload_registry.h
+++ b/webrtc/modules/rtp_rtcp/interface/rtp_payload_registry.h
@@ -83,7 +83,7 @@ class RTPPayloadRegistry {
 
   bool IsRtx(const RTPHeader& header) const;
 
-  bool RestoreOriginalPacket(uint8_t** restored_packet,
+  bool RestoreOriginalPacket(uint8_t* restored_packet,
                              const uint8_t* packet,
                              size_t* packet_length,
                              uint32_t original_ssrc,
@@ -138,6 +138,16 @@ class RTPPayloadRegistry {
     return last_received_media_payload_type_;
   };
 
+  bool use_rtx_payload_mapping_on_restore() const {
+    CriticalSectionScoped cs(crit_sect_.get());
+    return use_rtx_payload_mapping_on_restore_;
+  }
+
+  void set_use_rtx_payload_mapping_on_restore(bool val) {
+    CriticalSectionScoped cs(crit_sect_.get());
+    use_rtx_payload_mapping_on_restore_ = val;
+  }
+
  private:
   // Prunes the payload type map of the specific payload type, if it exists.
   void DeregisterAudioCodecOrRedTypeRegardlessOfPayloadType(
@@ -163,6 +173,9 @@ class RTPPayloadRegistry {
   int rtx_payload_type_;
   // Mapping rtx_payload_type_map_[rtx] = associated.
   std::map<int, int> rtx_payload_type_map_;
+  // When true, use rtx_payload_type_map_ when restoring RTX packets to get the
+  // correct payload type.
+  bool use_rtx_payload_mapping_on_restore_;
   uint32_t ssrc_rtx_;
 };