Update to current webrtc library

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

webrtc/api/rtp_headers.cc

@@ -0,0 +1,54 @@
+/*
+ *  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 "api/rtp_headers.h"
+
+namespace webrtc {
+
+RTPHeaderExtension::RTPHeaderExtension()
+    : hasTransmissionTimeOffset(false),
+      transmissionTimeOffset(0),
+      hasAbsoluteSendTime(false),
+      absoluteSendTime(0),
+      hasTransportSequenceNumber(false),
+      transportSequenceNumber(0),
+      hasAudioLevel(false),
+      voiceActivity(false),
+      audioLevel(0),
+      hasVideoRotation(false),
+      videoRotation(kVideoRotation_0),
+      hasVideoContentType(false),
+      videoContentType(VideoContentType::UNSPECIFIED),
+      has_video_timing(false) {}
+
+RTPHeaderExtension::RTPHeaderExtension(const RTPHeaderExtension& other) =
+    default;
+
+RTPHeaderExtension& RTPHeaderExtension::operator=(
+    const RTPHeaderExtension& other) = default;
+
+RTPHeader::RTPHeader()
+    : markerBit(false),
+      payloadType(0),
+      sequenceNumber(0),
+      timestamp(0),
+      ssrc(0),
+      numCSRCs(0),
+      arrOfCSRCs(),
+      paddingLength(0),
+      headerLength(0),
+      payload_type_frequency(0),
+      extension() {}
+
+RTPHeader::RTPHeader(const RTPHeader& other) = default;
+
+RTPHeader& RTPHeader::operator=(const RTPHeader& other) = default;
+
+}  // namespace webrtc