Fix bug where transport sequence numbers are allocated for packets without the header extension reg…

webrtc/modules/rtp_rtcp/source/rtp_sender.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_sender.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
index 25016e053f2b43a948f803846fda364423d31dbe..51d8c334799fc2a93ecfa09a415458fa0fa4e274 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
@@ -591,9 +591,9 @@ size_t RTPSender::SendPadData(size_t bytes,
   size_t padding_bytes_in_packet =
       std::min(MaxDataPayloadLength(), kMaxPaddingLength);
   size_t bytes_sent = 0;
-  bool using_transport_seq = rtp_header_extension_map_.IsRegistered(
-                                 kRtpExtensionTransportSequenceNumber) &&
-                             transport_sequence_number_allocator_;
+  bool using_transport_seq =
+      IsRtpHeaderExtensionRegistered(kRtpExtensionTransportSequenceNumber) &&
+      transport_sequence_number_allocator_;
   for (; bytes > 0; bytes -= padding_bytes_in_packet) {
     if (bytes < padding_bytes_in_packet)
       bytes = padding_bytes_in_packet;
@@ -647,9 +647,13 @@ size_t RTPSender::SendPadData(size_t bytes,
     }
 
     uint8_t padding_packet[IP_PACKET_SIZE];
-    size_t header_length =
-        CreateRtpHeader(padding_packet, payload_type, ssrc, false, timestamp,
-                        sequence_number, std::vector<uint32_t>());
+    size_t header_length = 0;
+    {
+      rtc::CritScope lock(&send_critsect_);
+      header_length =
+          CreateRtpHeader(padding_packet, payload_type, ssrc, false, timestamp,
+                          sequence_number, std::vector<uint32_t>());
+    }
     BuildPaddingPacket(padding_packet, header_length, padding_bytes_in_packet);
     size_t length = padding_bytes_in_packet + header_length;
     int64_t now_ms = clock_->TimeInMilliseconds();
@@ -666,7 +670,8 @@ size_t RTPSender::SendPadData(size_t bytes,
     UpdateAbsoluteSendTime(padding_packet, length, rtp_header, now_ms);
 
     PacketOptions options;
-    if (AllocateTransportSequenceNumber(&options.packet_id)) {
+    if (IsRtpHeaderExtensionRegistered(kRtpExtensionTransportSequenceNumber) &&
+        AllocateTransportSequenceNumber(&options.packet_id)) {
       if (UpdateTransportSequenceNumber(options.packet_id, padding_packet,
                                         length, rtp_header)) {
         if (transport_feedback_observer_)
@@ -859,7 +864,8 @@ bool RTPSender::PrepareAndSendPacket(uint8_t* buffer,
   UpdateAbsoluteSendTime(buffer_to_send_ptr, length, rtp_header, now_ms);
 
   PacketOptions options;
-  if (AllocateTransportSequenceNumber(&options.packet_id)) {
+  if (IsRtpHeaderExtensionRegistered(kRtpExtensionTransportSequenceNumber) &&
+      AllocateTransportSequenceNumber(&options.packet_id)) {
     if (UpdateTransportSequenceNumber(options.packet_id, buffer_to_send_ptr,
                                       length, rtp_header)) {
       if (transport_feedback_observer_)
@@ -992,7 +998,8 @@ int32_t RTPSender::SendToNetwork(uint8_t* buffer,
   }
 
   PacketOptions options;
-  if (AllocateTransportSequenceNumber(&options.packet_id)) {
+  if (IsRtpHeaderExtensionRegistered(kRtpExtensionTransportSequenceNumber) &&
+      AllocateTransportSequenceNumber(&options.packet_id)) {
     if (UpdateTransportSequenceNumber(options.packet_id, buffer, length,
                                       rtp_header)) {
       if (transport_feedback_observer_)