AGC2 config operator= and unit tests update

Bug: webrtc:7494
Change-Id: I7957602d60658b84175a617f9c283ea44eafe57d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/216260
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Reviewed-by: Sam Zackrisson <saza@google.com>
Cr-Commit-Position: refs/heads/master@{#33876}

modules/audio_processing/include/audio_processing.h

diff --git a/modules/audio_processing/include/audio_processing.h b/modules/audio_processing/include/audio_processing.h
index 8072230..9e6eed4 100644
--- a/modules/audio_processing/include/audio_processing.h
+++ b/modules/audio_processing/include/audio_processing.h
@@ -357,7 +357,13 @@
         float gain_db = 0.0f;
       } fixed_digital;
       struct AdaptiveDigital {
+        bool operator==(const AdaptiveDigital& rhs) const;
+        bool operator!=(const AdaptiveDigital& rhs) const {
+          return !(*this == rhs);
+        }
+
         bool enabled = false;
+        // Run the adaptive digital controller but the signal is not modified.
         bool dry_run = false;
         NoiseEstimator noise_estimator = kNoiseFloor;
         int vad_reset_period_ms = 1500;