Correcting the amount of padding when send side bwe includes RTP overhead.

webrtc/modules/rtp_rtcp/source/rtp_packet.h

 /*
  *  Copyright (c) 2016 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_MODULES_RTP_RTCP_SOURCE_RTP_PACKET_H_
@@ skipping 33 matching lines @@
   uint8_t PayloadType() const;
   uint16_t SequenceNumber() const;
   uint32_t Timestamp() const;
   uint32_t Ssrc() const;
   std::vector<uint32_t> Csrcs() const;
 
   // TODO(danilchap): Remove this function when all code update to use RtpPacket
   // directly. Function is there just for easier backward compatibilty.
   void GetHeader(RTPHeader* header) const;
 
-  size_t headers_size() const;
+  virtual size_t headers_size() const;
 
   // Payload.
   size_t payload_size() const;
   size_t padding_size() const;
   rtc::ArrayView<const uint8_t> payload() const;
 
   // Buffer.
   rtc::CopyOnWriteBuffer Buffer() const;
   size_t capacity() const;
-  size_t size() const;
+  virtual size_t size() const;
   const uint8_t* data() const;
   size_t FreeCapacity() const;
   size_t MaxPayloadSize() const;
 
   // Reset fields and buffer.
   void Clear();
 
   // Header setters.
   void CopyHeaderFrom(const Packet& packet);
   void SetMarker(bool marker_bit);
@@ skipping 111 matching lines @@
   uint16_t offset = 0;
   if (!AllocateExtension(Extension::kId, Extension::kValueSizeBytes, &offset))
     return false;
   memset(WriteAt(offset), 0, Extension::kValueSizeBytes);
   return true;
 }
 }  // namespace rtp
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_PACKET_H_