Remove hardcoded kValueSizeBytes values from variable-length header extensions.

webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.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 110 matching lines @@
 
 enum RtxMode {
   kRtxOff                 = 0x0,
   kRtxRetransmitted       = 0x1,  // Only send retransmissions over RTX.
   kRtxRedundantPayloads   = 0x2   // Preventively send redundant payloads
                                   // instead of padding.
 };
 
 const size_t kRtxHeaderSize = 2;
 
+struct RTPExtensionSizeInfo {

[danilchap, 2017/05/08 16:25:06]

may be RtpExtensionSize or RtpHeaderExtensionSize:
RTP -> Rtp to follow style guide (even if lots of types around do not)
drop Info because it doesn't seems to add descriptiveness and does look like
help avoiding name conflict.

[erikvarga1, 2017/05/09 11:40:03]

Done. I saw RTP in a few places so I thought that was the norm.

[danilchap, 2017/05/09 12:33:48]

May be hide this struct in less public header and move it closer to where it is
used.
e.g. to rtp_header_extension.h

[erikvarga1, 2017/05/09 13:30:30]

Done.

+  RTPExtensionType type;
+  uint8_t value_size;
+};
+
+template <typename Extension>
+constexpr RTPExtensionSizeInfo CreateExtensionSizeInfo() {

[danilchap, 2017/05/08 16:25:06]

planning to use this function outside of the rtp_rtcp module?

[erikvarga1, 2017/05/09 11:40:03]

I don't think so. This is used solely for the RTP extension overhead
calculation, so it shouldn't really be needed in other modules.

[danilchap, 2017/05/09 12:33:48]

Then do not declare it here:
it seems you use it in rtp_sender.cc and in a test.
Declare it just in rtp_sender.cc where you use it and in the test feel free to
inline the body.

[erikvarga1, 2017/05/09 13:30:30]

Done.

+  return {Extension::kId, Extension::kValueSizeBytes};
+}
+
 struct RTCPSenderInfo {
     uint32_t NTPseconds;
     uint32_t NTPfraction;
     uint32_t RTPtimeStamp;
     uint32_t sendPacketCount;
     uint32_t sendOctetCount;
 };
 
 struct RTCPReportBlock {
   RTCPReportBlock()
@@ skipping 304 matching lines @@
 class TransportSequenceNumberAllocator {
  public:
   TransportSequenceNumberAllocator() {}
   virtual ~TransportSequenceNumberAllocator() {}
 
   virtual uint16_t AllocateSequenceNumber() = 0;
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_RTP_RTCP_INCLUDE_RTP_RTCP_DEFINES_H_