Revert of Create RtcpDemuxer

webrtc/call/rtp_packet_sink_interface.h

 /*
  *  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.
  */
 #ifndef WEBRTC_CALL_RTP_PACKET_SINK_INTERFACE_H_
 #define WEBRTC_CALL_RTP_PACKET_SINK_INTERFACE_H_
 
 namespace webrtc {
 
 class RtpPacketReceived;
 
-// This class represents a receiver of already parsed RTP packets.
+// This class represents a receiver of an already parsed RTP packets.
 class RtpPacketSinkInterface {
  public:
-  virtual ~RtpPacketSinkInterface() = default;
+  virtual ~RtpPacketSinkInterface() {}
   virtual void OnRtpPacket(const RtpPacketReceived& packet) = 0;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_CALL_RTP_PACKET_SINK_INTERFACE_H_