message: Update nack tracker when receiving empty packets.
  Cr-Commit-Position: refs/heads/main@{#34958}
diff: @@ -195,11 +195,12 @@ int NetEqImpl::InsertPacket(const RTPHeader& rtp_header,
  return kOK;
  }
  -void NetEqImpl::InsertEmptyPacket(const RTPHeader& /*rtp_header*/) {
  - // TODO(henrik.lundin) Handle NACK as well. This will make use of the
  - // rtp_header parameter.
  - // https://bugs.chromium.org/p/webrtc/issues/detail?id=7611
  +void NetEqImpl::InsertEmptyPacket(const RTPHeader& rtp_header) {
  MutexLock lock(&mutex_);
  + if (nack_enabled_) {
  + nack_->UpdateLastReceivedPacket(rtp_header.sequenceNumber,
  + rtp_header.timestamp);
  + }
  controller_->RegisterEmptyPacket();
  }
  