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/optionally_built_submodule_creators.cc

@@ -0,0 +1,31 @@
+/*
+ *  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.
+ */
+
+#include "modules/audio_processing/optionally_built_submodule_creators.h"
+
+#include <memory>
+
+#include "modules/audio_processing/transient/transient_suppressor_impl.h"
+
+namespace webrtc {
+
+std::unique_ptr<TransientSuppressor> CreateTransientSuppressor(
+    const ApmSubmoduleCreationOverrides& overrides) {
+#ifdef WEBRTC_EXCLUDE_TRANSIENT_SUPPRESSOR
+  return nullptr;
+#else
+  if (overrides.transient_suppression) {
+    return nullptr;
+  }
+  return std::make_unique<TransientSuppressorImpl>();
+#endif
+}
+
+}  // namespace webrtc