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/agc2/cpu_features.h

@@ -0,0 +1,39 @@
+/*
+ *  Copyright (c) 2020 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_AGC2_CPU_FEATURES_H_
+#define MODULES_AUDIO_PROCESSING_AGC2_CPU_FEATURES_H_
+
+#include <string>
+
+namespace webrtc {
+
+// Collection of flags indicating which CPU features are available on the
+// current platform. True means available.
+struct AvailableCpuFeatures {
+  AvailableCpuFeatures(bool sse2, bool avx2, bool neon)
+      : sse2(sse2), avx2(avx2), neon(neon) {}
+  // Intel.
+  bool sse2;
+  bool avx2;
+  // ARM.
+  bool neon;
+  std::string ToString() const;
+};
+
+// Detects what CPU features are available.
+AvailableCpuFeatures GetAvailableCpuFeatures();
+
+// Returns the CPU feature flags all set to false.
+AvailableCpuFeatures NoAvailableCpuFeatures();
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC2_CPU_FEATURES_H_