Update to current webrtc library

This is from the upstream library commit id
3326535126e435f1ba647885ce43a8f0f3d317eb, corresponding to Chromium
88.0.4290.1.

webrtc/modules/audio_processing/aec3/echo_path_variability.cc

@@ -0,0 +1,22 @@
+/*
+ *  Copyright (c) 2017 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/echo_path_variability.h"
+
+namespace webrtc {
+
+EchoPathVariability::EchoPathVariability(bool gain_change,
+                                         DelayAdjustment delay_change,
+                                         bool clock_drift)
+    : gain_change(gain_change),
+      delay_change(delay_change),
+      clock_drift(clock_drift) {}
+
+}  // namespace webrtc