Reland "Reduce the amount of howling reduction in AEC3"

This is a reland of 2978abb88c49362e296bdce3cb662f6255b17083

Original change's description:
> Reduce the amount of howling reduction in AEC3
>
> This CL backs off the howling protection functionality in AEC3.
> The effect is increased transparency in some cases. No negative effects
> have been identified in the hands-on testing.
>
>
> A kill-switch is added that can be used to turn off the functionality.
>
> Bug: b/150764764
> Change-Id: I604c569c76f911799556a60bc8fd2fb43bbfe196
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/186082
> Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
> Commit-Queue: Per Åhgren <peah@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#32258}

Bug: b/150764764
Change-Id: I277f24eb3288ad0307e7463bad9aea6436cfe879
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/186263
Reviewed-by: Per Åhgren <peah@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32274}

1 files changed, 6 insertions, 0 deletions

diff --git a/modules/audio_processing/aec3/echo_canceller3.cc b/modules/audio_processing/aec3/echo_canceller3.cc
index d96abc979f..4b67df0eee 100644
--- a/modules/audio_processing/aec3/echo_canceller3.cc
+++ b/modules/audio_processing/aec3/echo_canceller3.cc
@@ -213,6 +213,12 @@ void CopyBufferIntoFrame(const AudioBuffer& buffer,
 EchoCanceller3Config AdjustConfig(const EchoCanceller3Config& config) {
   EchoCanceller3Config adjusted_cfg = config;
 
+  if (field_trial::IsEnabled("WebRTC-Aec3AntiHowlingMinimizationKillSwitch")) {
+    adjusted_cfg.suppressor.high_bands_suppression
+        .anti_howling_activation_threshold = 25.f;
+    adjusted_cfg.suppressor.high_bands_suppression.anti_howling_gain = 0.01f;
+  }
+
   if (field_trial::IsEnabled("WebRTC-Aec3UseShortConfigChangeDuration")) {
     adjusted_cfg.filter.config_change_duration_blocks = 10;
   }