Merge of the AEC3 Tuning changes.

This CL is a merge of 103ac7e into
M59.

This CL adds tuning to AEC3 for the purpose of reducing the impact of
gain changes in the analog microphone gain.
NOTRY=true
NOPRESUBMIT=true
BUG=chromium:710818, webrtc:6018

Review-Url: https://codereview.webrtc.org/2811283003
Cr-Commit-Position: refs/heads/master@{#17673}
(cherry picked from commit 103ac7e)

Review-Url: https://codereview.webrtc.org/2833643003
Cr-Commit-Position: refs/branch-heads/59@{#3}
Cr-Branched-From: 10d095d-refs/heads/master@{#17657}

Author: peah

webrtc/modules/audio_processing/aec3/aec_state.cc

@@ -72,7 +72,7 @@ rtc::Optional<size_t> EstimateFilterDelay(
 }
 
 constexpr int kEchoPathChangeCounterInitial = kNumBlocksPerSecond / 5;
-constexpr int kEchoPathChangeCounterMax = 3 * kNumBlocksPerSecond;
+constexpr int kEchoPathChangeCounterMax = 2 * kNumBlocksPerSecond;
 
 }  // namespace
 
@@ -90,17 +90,19 @@ void AecState::HandleEchoPathChange(
   if (echo_path_variability.AudioPathChanged()) {
     blocks_since_last_saturation_ = 0;
     active_render_blocks_ = 0;
-    echo_path_change_counter_ = kEchoPathChangeCounterMax;
     usable_linear_estimate_ = false;
     echo_leakage_detected_ = false;
     capture_signal_saturation_ = false;
     echo_saturation_ = false;
-    headset_detected_ = false;
     previous_max_sample_ = 0.f;
 
     if (echo_path_variability.delay_change) {
       force_zero_gain_counter_ = 0;
       force_zero_gain_ = true;
+      echo_path_change_counter_ = kEchoPathChangeCounterMax;
+    }
+    if (echo_path_variability.gain_change) {
+      echo_path_change_counter_ = kEchoPathChangeCounterInitial;
     }
   }
 }

webrtc/modules/audio_processing/audio_processing_impl.cc

@@ -10,6 +10,7 @@
 
 #include "webrtc/modules/audio_processing/audio_processing_impl.h"
 
+#include <math.h>
 #include <algorithm>
 
 #include "webrtc/base/checks.h"
@@ -1147,7 +1148,7 @@ int AudioProcessingImpl::ProcessCaptureStreamLocked() {
   if (private_submodules_->echo_canceller3) {
     const int new_agc_level = gain_control()->stream_analog_level();
     capture_.echo_path_gain_change =
-        (capture_.previous_agc_level != new_agc_level);
+        abs(capture_.previous_agc_level - new_agc_level) > 5;
     capture_.previous_agc_level = new_agc_level;
     private_submodules_->echo_canceller3->AnalyzeCapture(capture_buffer);
   }