Bump to WebRTC M120 release

Some API deprecation -- ExperimentalAgc and ExperimentalNs are gone.
We're continuing to carry iSAC even though it's gone upstream, but maybe
we'll want to drop that soon.

webrtc/modules/audio_processing/aec3/config_selector.cc

@@ -0,0 +1,71 @@
+
+/*
+ *  Copyright (c) 2022 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/audio_processing/aec3/config_selector.h"
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+namespace {
+
+// Validates that the mono and the multichannel configs have compatible fields.
+bool CompatibleConfigs(const EchoCanceller3Config& mono_config,
+                       const EchoCanceller3Config& multichannel_config) {
+  if (mono_config.delay.fixed_capture_delay_samples !=
+      multichannel_config.delay.fixed_capture_delay_samples) {
+    return false;
+  }
+  if (mono_config.filter.export_linear_aec_output !=
+      multichannel_config.filter.export_linear_aec_output) {
+    return false;
+  }
+  if (mono_config.filter.high_pass_filter_echo_reference !=
+      multichannel_config.filter.high_pass_filter_echo_reference) {
+    return false;
+  }
+  if (mono_config.multi_channel.detect_stereo_content !=
+      multichannel_config.multi_channel.detect_stereo_content) {
+    return false;
+  }
+  if (mono_config.multi_channel.stereo_detection_timeout_threshold_seconds !=
+      multichannel_config.multi_channel
+          .stereo_detection_timeout_threshold_seconds) {
+    return false;
+  }
+  return true;
+}
+
+}  // namespace
+
+ConfigSelector::ConfigSelector(
+    const EchoCanceller3Config& config,
+    const absl::optional<EchoCanceller3Config>& multichannel_config,
+    int num_render_input_channels)
+    : config_(config), multichannel_config_(multichannel_config) {
+  if (multichannel_config_.has_value()) {
+    RTC_DCHECK(CompatibleConfigs(config_, *multichannel_config_));
+  }
+
+  Update(!config_.multi_channel.detect_stereo_content &&
+         num_render_input_channels > 1);
+
+  RTC_DCHECK(active_config_);
+}
+
+void ConfigSelector::Update(bool multichannel_content) {
+  if (multichannel_content && multichannel_config_.has_value()) {
+    active_config_ = &(*multichannel_config_);
+  } else {
+    active_config_ = &config_;
+  }
+}
+
+}  // namespace webrtc