Always send RED headers if configured.

webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
index 0bf95b7fe4b14f10d60d4cea44504d5a2083ee0e..e10b5b2edab45b98689b1d1fec6346bd1115f3b9 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
@@ -36,8 +36,8 @@ RTPSenderVideo::RTPSenderVideo(Clock* clock, RTPSenderInterface* rtpSender)
       // Generic FEC
       fec_(),
       fec_enabled_(false),
-      red_payload_type_(-1),
-      fec_payload_type_(-1),
+      red_payload_type_(0),
+      fec_payload_type_(0),
       delta_fec_params_(),
       key_fec_params_(),
       producer_fec_(&fec_),
@@ -191,16 +191,19 @@ void RTPSenderVideo::GenericFECStatus(bool* enable,
 
 size_t RTPSenderVideo::FECPacketOverhead() const {
   rtc::CritScope cs(&crit_);
-  if (fec_enabled_) {
+  size_t overhead = 0;
+  if (red_payload_type_ != 0) {
     // Overhead is FEC headers plus RED for FEC header plus anything in RTP
     // header beyond the 12 bytes base header (CSRC list, extensions...)
     // This reason for the header extensions to be included here is that
     // from an FEC viewpoint, they are part of the payload to be protected.
     // (The base RTP header is already protected by the FEC header.)
-    return ForwardErrorCorrection::PacketOverhead() + REDForFECHeaderLength +
-           (_rtpSender.RTPHeaderLength() - kRtpHeaderSize);
+    overhead = REDForFECHeaderLength + (_rtpSender.RTPHeaderLength() -
+      kRtpHeaderSize);
   }
-  return 0;
+  if (fec_enabled_)
+    overhead += ForwardErrorCorrection::PacketOverhead();
+  return overhead;
 }
 
 void RTPSenderVideo::SetFecParameters(const FecProtectionParams* delta_params,
@@ -208,8 +211,10 @@ void RTPSenderVideo::SetFecParameters(const FecProtectionParams* delta_params,
   rtc::CritScope cs(&crit_);
   RTC_DCHECK(delta_params);
   RTC_DCHECK(key_params);
-  delta_fec_params_ = *delta_params;
-  key_fec_params_ = *key_params;
+  if (fec_enabled_) {
+    delta_fec_params_ = *delta_params;
+    key_fec_params_ = *key_params;
+  }
 }
 
 int32_t RTPSenderVideo::SendVideo(const RtpVideoCodecTypes videoType,
@@ -230,7 +235,7 @@ int32_t RTPSenderVideo::SendVideo(const RtpVideoCodecTypes videoType,
       video_header ? &(video_header->codecHeader) : nullptr, frameType));
 
   StorageType storage;
-  bool fec_enabled;
+  int red_payload_type;
   bool first_frame = first_frame_sent_();
   {
     rtc::CritScope cs(&crit_);
@@ -238,7 +243,7 @@ int32_t RTPSenderVideo::SendVideo(const RtpVideoCodecTypes videoType,
         frameType == kVideoFrameKey ? &key_fec_params_ : &delta_fec_params_;
     producer_fec_.SetFecParameters(fec_params, 0);
     storage = packetizer->GetStorageType(_retransmissionSettings);
-    fec_enabled = fec_enabled_;
+    red_payload_type = red_payload_type_;
   }
 
   // Register CVO rtp header extension at the first time when we receive a frame
@@ -301,7 +306,7 @@ int32_t RTPSenderVideo::SendVideo(const RtpVideoCodecTypes videoType,
       _rtpSender.UpdateVideoRotation(dataBuffer, packetSize, rtp_header,
                                      video_header->rotation);
     }
-    if (fec_enabled) {
+    if (red_payload_type != 0) {
       SendVideoPacketAsRed(dataBuffer, payload_bytes_in_packet,
                            rtp_header_length, _rtpSender.SequenceNumber(),
                            captureTimeStamp, capture_time_ms, storage,