Fixing crash that may occur after destroying a VideoSendStream.

webrtc/video/video_send_stream.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 431 matching lines @@
 
   module_process_thread_->RegisterModule(&overuse_detector_);
 
   encoder_thread_.Start();
   encoder_thread_.SetPriority(rtc::kHighPriority);
 }
 
 VideoSendStream::~VideoSendStream() {
   LOG(LS_INFO) << "~VideoSendStream: " << config_.ToString();
 
-  bitrate_allocator_->RemoveObserver(this);
   Stop();
 
   // Stop the encoder thread permanently.
   rtc::AtomicOps::ReleaseStore(&stop_encoder_thread_, 1);
   encoder_wakeup_event_.Set();
   encoder_thread_.Stop();
 
+  // This needs to happen after stopping the encoder thread,
+  // since the encoder thread calls AddObserver.
+  bitrate_allocator_->RemoveObserver(this);
+
   module_process_thread_->DeRegisterModule(&overuse_detector_);
   vie_channel_.RegisterSendFrameCountObserver(nullptr);
   vie_channel_.RegisterSendBitrateObserver(nullptr);
   vie_channel_.RegisterRtcpPacketTypeCounterObserver(nullptr);
 
   call_stats_->DeregisterStatsObserver(vie_channel_.GetStatsObserver());
   rtp_rtcp_modules_[0]->SetREMBStatus(false);
   remb_->RemoveRembSender(rtp_rtcp_modules_[0]);
 
   // ViEChannel outlives ViEEncoder so remove encoder from feedback before
@@ skipping 190 matching lines @@
 }
 
 void VideoSendStream::OnBitrateUpdated(uint32_t bitrate_bps,
                                        uint8_t fraction_loss,
                                        int64_t rtt) {
   vie_encoder_.OnBitrateUpdated(bitrate_bps, fraction_loss, rtt);
 }
 
 }  // namespace internal
 }  // namespace webrtc