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.h

@@ -0,0 +1,41 @@
+/*
+ *  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.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_AEC3_CONFIG_SELECTOR_H_
+#define MODULES_AUDIO_PROCESSING_AEC3_CONFIG_SELECTOR_H_
+
+#include "absl/types/optional.h"
+#include "api/audio/echo_canceller3_config.h"
+
+namespace webrtc {
+
+// Selects the config to use.
+class ConfigSelector {
+ public:
+  ConfigSelector(
+      const EchoCanceller3Config& config,
+      const absl::optional<EchoCanceller3Config>& multichannel_config,
+      int num_render_input_channels);
+
+  // Updates the config selection based on the detection of multichannel
+  // content.
+  void Update(bool multichannel_content);
+
+  const EchoCanceller3Config& active_config() const { return *active_config_; }
+
+ private:
+  const EchoCanceller3Config config_;
+  const absl::optional<EchoCanceller3Config> multichannel_config_;
+  const EchoCanceller3Config* active_config_ = nullptr;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AEC3_CONFIG_SELECTOR_H_