Use the new AudioProcessing statistics everywhere.

The new interface uses optionals instead of default values, and only values that are actually used are included. To make it easy to add/remove stats in the future, the struct itself is copied around on all layers, instead of copying the values one by one. This CL also fixes a bug which caused several APM statistics to get stuck at a fixed level when there are no more receive streams (after some period where there were receive streams). Since APM doesn't know this happens, an argument was added to the GetStats call to pass this information down to APM.

Bug: webrtc:8563, b/67926135
Change-Id: I96cc008353355bb520c4523f5c5379860f73ee24
Reviewed-on: https://webrtc-review.googlesource.com/25621
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20877}
diff --git a/modules/audio_processing/include/audio_processing.h b/modules/audio_processing/include/audio_processing.h
index a4245c6..6c8f4db 100644
--- a/modules/audio_processing/include/audio_processing.h
+++ b/modules/audio_processing/include/audio_processing.h
@@ -22,6 +22,7 @@
 
 #include "api/optional.h"
 #include "modules/audio_processing/beamformer/array_util.h"
+#include "modules/audio_processing/include/audio_processing_statistics.h"
 #include "modules/audio_processing/include/config.h"
 #include "rtc_base/arraysize.h"
 #include "rtc_base/deprecation.h"
@@ -564,38 +565,6 @@
     float residual_echo_likelihood_recent_max = -1.0f;
   };
 
-  // This version of the stats uses Optionals, it will replace the regular
-  // AudioProcessingStatistics struct.
-  struct AudioProcessingStats {
-    AudioProcessingStats();
-    AudioProcessingStats(const AudioProcessingStats& other);
-    ~AudioProcessingStats();
-
-    // AEC Statistics.
-    // ERL = 10log_10(P_far / P_echo)
-    rtc::Optional<double> echo_return_loss;
-    // ERLE = 10log_10(P_echo / P_out)
-    rtc::Optional<double> echo_return_loss_enhancement;
-    // Fraction of time that the AEC linear filter is divergent, in a 1-second
-    // non-overlapped aggregation window.
-    rtc::Optional<double> divergent_filter_fraction;
-
-    // The delay metrics consists of the delay median and standard deviation. It
-    // also consists of the fraction of delay estimates that can make the echo
-    // cancellation perform poorly. The values are aggregated until the first
-    // call to |GetStatistics()| and afterwards aggregated and updated every
-    // second. Note that if there are several clients pulling metrics from
-    // |GetStatistics()| during a session the first call from any of them will
-    // change to one second aggregation window for all.
-    rtc::Optional<int32_t> delay_median_ms;
-    rtc::Optional<int32_t> delay_standard_deviation_ms;
-
-    // Residual echo detector likelihood.
-    rtc::Optional<double> residual_echo_likelihood;
-    // Maximum residual echo likelihood from the last time period.
-    rtc::Optional<double> residual_echo_likelihood_recent_max;
-  };
-
   // TODO(ivoc): Make this pure virtual when all subclasses have been updated.
   virtual AudioProcessingStatistics GetStatistics() const;