Add overhead per packet observer to the rtp_sender.

webrtc/common_types.h

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 281 matching lines @@
 // TODO(asapersson): This class will remove the need for SendSideDelayObserver.
 // Remove SendSideDelayObserver once possible.
 class SendPacketObserver {
  public:
   virtual ~SendPacketObserver() {}
   virtual void OnSendPacket(uint16_t packet_id,
                             int64_t capture_time_ms,
                             uint32_t ssrc) = 0;
 };
 
+// Callback, used to notify an observer when the overhead per packet
+// has changed.
+class OverheadObserver {
+ public:
+  virtual ~OverheadObserver() = default;
+  virtual void OnOverheadChanged(size_t overhead_bytes_per_packet) = 0;
+};
+
 // ==================================================================
 // Voice specific types
 // ==================================================================
 
 // Each codec supported can be described by this structure.
 struct CodecInst {
   int pltype;
   char plname[RTP_PAYLOAD_NAME_SIZE];
   int plfreq;
   int pacsize;
@@ skipping 559 matching lines @@
 enum class RtcpMode { kOff, kCompound, kReducedSize };
 
 enum NetworkState {
   kNetworkUp,
   kNetworkDown,
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_COMMON_TYPES_H_