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 bd2a250f6653cc7d031a76c4d9075610c6d25138..8e76db268cf42c7df8b2315d65c0652b11d8b17d 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_;
+
+  ANAStats stats_;
+
+  const bool enable_bitrate_adaptation_;
+  const bool enable_dtx_adaptation_;
+  const bool enable_fec_adaptation_;
+  const bool enable_channel_adaptation_;
+  const bool enable_frame_length_adaptation_;
+
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioNetworkAdaptorImpl);
 };