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/block_buffer.cc

@@ -0,0 +1,39 @@
+/*
+ *  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/block_buffer.h"
+
+#include <algorithm>
+
+namespace webrtc {
+
+BlockBuffer::BlockBuffer(size_t size,
+                         size_t num_bands,
+                         size_t num_channels,
+                         size_t frame_length)
+    : size(static_cast<int>(size)),
+      buffer(size,
+             std::vector<std::vector<std::vector<float>>>(
+                 num_bands,
+                 std::vector<std::vector<float>>(
+                     num_channels,
+                     std::vector<float>(frame_length, 0.f)))) {
+  for (auto& block : buffer) {
+    for (auto& band : block) {
+      for (auto& channel : band) {
+        std::fill(channel.begin(), channel.end(), 0.f);
+      }
+    }
+  }
+}
+
+BlockBuffer::~BlockBuffer() = default;
+
+}  // namespace webrtc