Simplify {,Set}UlpfecConfig interface.

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 72425671599b06321eeae1ae56e1de20a2a505d9..9838da7104bce62c84ca45bad4b8c77c55c80b58 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
@@ -170,28 +170,33 @@ void RTPSenderVideo::SendVideoPacketAsRed(
   }
 }
 
-void RTPSenderVideo::SetUlpfecConfig(bool enabled,
-                                     int red_payload_type,
+void RTPSenderVideo::SetUlpfecConfig(int red_payload_type,
                                      int ulpfec_payload_type) {
-  RTC_DCHECK(!enabled || red_payload_type > 0);
+  // Sanity check. Per the definition of UlpfecConfig (see config.h),
+  // a payload type of -1 means that the corresponding feature is
+  // turned off.
+  RTC_DCHECK_GE(red_payload_type, -1);
   RTC_DCHECK_LE(red_payload_type, 127);
+  RTC_DCHECK_GE(ulpfec_payload_type, -1);
   RTC_DCHECK_LE(ulpfec_payload_type, 127);
 
   rtc::CritScope cs(&crit_);
-  fec_enabled_ = enabled;
   red_payload_type_ = red_payload_type;
+  red_enabled_ = (red_payload_type_ != -1);
   fec_payload_type_ = ulpfec_payload_type;
+  fec_enabled_ = (fec_payload_type_ != -1);
+
+  // TODO(brandtr): Remove when the RED/RTX workaround is removed.
+  RTC_DCHECK(red_enabled_ || !fec_enabled_);
 
   // Reset FEC rates.
   delta_fec_params_ = FecProtectionParams{0, 1, kFecMaskRandom};
   key_fec_params_ = FecProtectionParams{0, 1, kFecMaskRandom};
 }
 
-void RTPSenderVideo::UlpfecConfig(bool* enabled,
-                                  int* red_payload_type,
+void RTPSenderVideo::UlpfecConfig(int* red_payload_type,
                                   int* ulpfec_payload_type) const {
   rtc::CritScope cs(&crit_);
-  *enabled = fec_enabled_;
   *red_payload_type = red_payload_type_;
   *ulpfec_payload_type = fec_payload_type_;
 }
@@ -199,7 +204,7 @@ void RTPSenderVideo::UlpfecConfig(bool* enabled,
 size_t RTPSenderVideo::FecPacketOverhead() const {
   rtc::CritScope cs(&crit_);
   size_t overhead = 0;
-  if (red_payload_type_ != -1) {
+  if (red_enabled_) {
     // 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
@@ -272,7 +277,7 @@ bool RTPSenderVideo::SendVideo(RtpVideoCodecTypes video_type,
       video_header ? &(video_header->codecHeader) : nullptr, frame_type));
 
   StorageType storage;
-  int red_payload_type;
+  bool red_enabled;
   bool first_frame = first_frame_sent_();
   {
     rtc::CritScope cs(&crit_);
@@ -280,7 +285,7 @@ bool RTPSenderVideo::SendVideo(RtpVideoCodecTypes video_type,
         frame_type == kVideoFrameKey ? &key_fec_params_ : &delta_fec_params_;
     producer_fec_.SetFecParameters(fec_params);
     storage = packetizer->GetStorageType(retransmission_settings_);
-    red_payload_type = red_payload_type_;
+    red_enabled = red_enabled_;
   }
 
   // TODO(changbin): we currently don't support to configure the codec to
@@ -307,7 +312,7 @@ bool RTPSenderVideo::SendVideo(RtpVideoCodecTypes video_type,
     if (!rtp_sender_->AssignSequenceNumber(packet.get()))
       return false;
 
-    if (red_payload_type != -1) {
+    if (red_enabled) {
       SendVideoPacketAsRed(std::move(packet), storage,
                            packetizer->GetProtectionType() == kProtectedPacket);
     } else {