Revert of Create RtcpDemuxer

webrtc/call/rtp_rtcp_demuxer_helper.cc

-/*
- *  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 "webrtc/call/rtp_rtcp_demuxer_helper.h"
-
-#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/bye.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/common_header.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/extended_reports.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/psfb.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/receiver_report.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/sender_report.h"
-
-namespace webrtc {
-
-rtc::Optional<uint32_t> ParseRtcpPacketSenderSsrc(
-    rtc::ArrayView<const uint8_t> packet) {
-  rtcp::CommonHeader header;
-  for (const uint8_t* next_packet = packet.begin(); next_packet < packet.end();
-       next_packet = header.NextPacket()) {
-    if (!header.Parse(next_packet, packet.end() - next_packet)) {
-      return rtc::Optional<uint32_t>();
-    }
-
-    switch (header.type()) {
-      case rtcp::Bye::kPacketType:
-      case rtcp::ExtendedReports::kPacketType:
-      case rtcp::Psfb::kPacketType:
-      case rtcp::ReceiverReport::kPacketType:
-      case rtcp::Rtpfb::kPacketType:
-      case rtcp::SenderReport::kPacketType: {
-        // Sender SSRC at the beginning of the RTCP payload.
-        if (header.payload_size_bytes() >= sizeof(uint32_t)) {
-          const uint32_t ssrc_sender =
-              ByteReader<uint32_t>::ReadBigEndian(header.payload());
-          return rtc::Optional<uint32_t>(ssrc_sender);
-        } else {
-          return rtc::Optional<uint32_t>();
-        }
-      }
-    }
-  }
-
-  return rtc::Optional<uint32_t>();
-}
-
-}  // namespace webrtc