Update smoothed bitrate.

webrtc/voice_engine/channel.cc

Index: webrtc/voice_engine/channel.cc
diff --git a/webrtc/voice_engine/channel.cc b/webrtc/voice_engine/channel.cc
index 6e2e91c0a1bd0c0e62ccc4a753ef940d12ec2849..fbb8b9c96714bb2afd65605e538953e645ad14b3 100644
--- a/webrtc/voice_engine/channel.cc
+++ b/webrtc/voice_engine/channel.cc
@@ -1351,14 +1351,9 @@ void Channel::SetBitRate(int bitrate_bps, int64_t probing_interval_ms) {
   // the next probing, we would choose a time constant that fulfills
   // 1 - e^(-probing_interval_ms / time_constant) < 0.25
   // Then 4 * probing_interval_ms is a good choice.
+  rtc::CritScope lock(&bitrate_smoother_lock_);
   bitrate_smoother_.SetTimeConstantMs(probing_interval_ms * 4);
-  bitrate_smoother_.AddSample(bitrate_bps);
-  audio_coding_->ModifyEncoder([&](std::unique_ptr<AudioEncoder>* encoder) {
-    if (*encoder) {
-      (*encoder)->OnReceivedUplinkBandwidth(
-          static_cast<int>(*bitrate_smoother_.GetAverage()));
-    }
-  });
+  bitrate_bps_ = rtc::Optional<int>(bitrate_bps);
 }
 
 void Channel::OnIncomingFractionLoss(int fraction_lost) {
@@ -2755,6 +2750,19 @@ void Channel::SetNACKStatus(bool enable, int maxNumberOfPackets) {
     audio_coding_->DisableNack();
 }
 
+void Channel::AdaptCodec() {
+  audio_coding_->ModifyEncoder([&](std::unique_ptr<AudioEncoder>* encoder) {
+    rtc::CritScope lock(&bitrate_smoother_lock_);

[the sun, 2016/12/13 16:43:24]

Which threads can we be running on? Is it possible to use a thread checker
instead?

[michaelt, 2016/12/13 17:01:26]

No, since AdaptCodec() runs on the worker queue. And SetBitRate on the network
thread.

+    if (bitrate_bps_) {
+      bitrate_smoother_.AddSample(*bitrate_bps_);
+      if (*encoder) {
+        (*encoder)->OnReceivedUplinkBandwidth(
+            static_cast<int>(*bitrate_smoother_.GetAverage()));
+      }
+    }
+  });
+}
+
 // Called when we are missing one or more packets.
 int Channel::ResendPackets(const uint16_t* sequence_numbers, int length) {
   return _rtpRtcpModule->SendNACK(sequence_numbers, length);