Protected streams report RTP messages directly to the FlexFec streams

webrtc/modules/rtp_rtcp/source/flexfec_receiver.cc

Index: webrtc/modules/rtp_rtcp/source/flexfec_receiver.cc
diff --git a/webrtc/modules/rtp_rtcp/source/flexfec_receiver.cc b/webrtc/modules/rtp_rtcp/source/flexfec_receiver.cc
index 454f32798ac8a5adcd69bd9b3966aa108c59d2dc..5564cd6556eea3a99bb73b2a15452740f6cfd22c 100644
--- a/webrtc/modules/rtp_rtcp/source/flexfec_receiver.cc
+++ b/webrtc/modules/rtp_rtcp/source/flexfec_receiver.cc
@@ -59,6 +59,8 @@ FecPacketCounter FlexfecReceiver::GetPacketCounter() const {
   return packet_counter_;
 }
 
+// TODO(eladalon): Consider using packet.recovered() to avoid processing
+// recovered packets here.
 bool FlexfecReceiver::AddReceivedPacket(const RtpPacketReceived& packet) {
   RTC_DCHECK_CALLED_SEQUENTIALLY(&sequence_checker_);
 
@@ -93,6 +95,11 @@ bool FlexfecReceiver::AddReceivedPacket(const RtpPacketReceived& packet) {
     if (received_packet->ssrc != protected_media_ssrc_) {
       return false;
     }
+    // TODO(eladalon): It seems like, because of return-statement above,

[danilchap, 2017/07/24 15:37:25]

received_packet is a local variable: if return above, it will be destroyed.
only below it is pushed into member variable for later use.

[eladalon, 2017/07/24 15:53:55]

Right you are. Looks like I was confused between |received_packet| and |packet|
(which is const) when I filed this bug. At least, that's one theory for the
mistake.

+    // it could be that nobody ever ends up updating |is_fec|. Specifically,
+    // it seems like a media packet would never be set to |is_fec=false|
+    // if there is no FlexFEC stream protecting it.
+    // https://bugs.chromium.org/p/webrtc/issues/detail?id=7954
     received_packet->is_fec = false;
 
     // Insert entire packet into erasure code.