Implement ANA statistics.

webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl.h

Index: webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl.h
diff --git a/webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl.h b/webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl.h
index bb0a0aabdbe5dcae54c9ec0780626ad63c374f1b..aa103b23889cd0105d16d9f4302ce274ddeb2170 100644
--- a/webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl.h
+++ b/webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl.h
@@ -75,6 +75,16 @@ class AudioNetworkAdaptorImpl final : public AudioNetworkAdaptor {
 
   Controller::NetworkMetrics last_metrics_;
 
+  rtc::Optional<AudioEncoderRuntimeConfig> prev_config_;
+
+  AudioNetworkAdaptorStats stats_;
+
+  bool enable_bitrate_adaptation_ = true;

[minyue-webrtc, 2017/09/01 14:52:13]

My comment:

 add const, 

then you need to
1. no assignment here (natural follow-up of 1)
2. put these in initializer list  

[ivoc, 2017/09/05 09:01:40]

Done

+  bool enable_dtx_adaptation_ = true;
+  bool enable_fec_adaptation_ = true;
+  bool enable_channel_adaptation_ = true;
+  bool enable_frame_length_adaptation_ = true;
+
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioNetworkAdaptorImpl);
 };