Propagate SDP negotiation of extmap-allow-mixed to RtpHeaderExtensionMap

Bug: webrtc:7990
Change-Id: I662595f90b9d0be39f7e14752e13b2bb7a1746ee
Reviewed-on: https://webrtc-review.googlesource.com/c/106020
Reviewed-by: Seth Hampson <shampson@webrtc.org>
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Johannes Kron <kron@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25421}
diff --git a/audio/channel_send.cc b/audio/channel_send.cc
index 4490b19..cc8b1f7 100644
--- a/audio/channel_send.cc
+++ b/audio/channel_send.cc
@@ -453,7 +453,8 @@
                          RtcpRttStats* rtcp_rtt_stats,
                          RtcEventLog* rtc_event_log,
                          FrameEncryptorInterface* frame_encryptor,
-                         const webrtc::CryptoOptions& crypto_options)
+                         const webrtc::CryptoOptions& crypto_options,
+                         bool extmap_allow_mixed)
     : event_log_(rtc_event_log),
       _timeStamp(0),  // This is just an offset, RTP module will add it's own
                       // random offset
@@ -496,6 +497,7 @@
   configuration.rtt_stats = rtcp_rtt_stats;
   configuration.retransmission_rate_limiter =
       retransmission_rate_limiter_.get();
+  configuration.extmap_allow_mixed = extmap_allow_mixed;
 
   _rtpRtcpModule.reset(RtpRtcp::CreateRtpRtcp(configuration));
   _rtpRtcpModule->SetSendingMediaStatus(false);
@@ -836,6 +838,10 @@
   _rtpRtcpModule->SetMid(mid);
 }
 
+void ChannelSend::SetExtmapAllowMixed(bool extmap_allow_mixed) {
+  _rtpRtcpModule->SetExtmapAllowMixed(extmap_allow_mixed);
+}
+
 int ChannelSend::SetSendAudioLevelIndicationStatus(bool enable,
                                                    unsigned char id) {
   _includeAudioLevelIndication = enable;