Set actual transport overhead in rtp_rtcp

webrtc/modules/rtp_rtcp/include/rtp_rtcp.h

Index: webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
diff --git a/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h b/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
index 9fa3959c906128a81596a7fc8f97e9a269167bbc..8c6ed0ffe003622f864e14e5b693a7821c019a8b 100644
--- a/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
+++ b/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
@@ -109,15 +109,10 @@ class RtpRtcp : public Module {
   // Returns -1 on failure else 0.
   virtual int32_t SetMaxTransferUnit(uint16_t size) = 0;
 
-  // Sets transtport overhead. Default is IPv4 and UDP with no encryption.
-  // |tcp| - true for TCP false UDP.
-  // |ipv6| - true for IP version 6 false for version 4.
-  // |authentication_overhead| - number of bytes to leave for an authentication
-  // header.
+  // Sets transtport overhead per packet.
   // Returns -1 on failure else 0
-  virtual int32_t SetTransportOverhead(bool tcp,
-                                       bool ipv6,
-                                       uint8_t authentication_overhead = 0) = 0;
+  virtual int32_t SetTransportOverhead(

[minyue-webrtc, 2016/10/20 09:45:22]

Removing/Modifying API may require to send some notice to webrtc-discussion 2
weeks ahead of time. 

Easy way is to 

1) keep the old one, let new one direct to the old one
2) prepare a separate cleaning up CL and send to webrtc-discussion, then you can
land this CL first
3) after two weeks time without objection, land the cleaning up CL.

[the sun, 2016/10/20 10:40:52]

Sorry, I didn't think about the rtprtcp module being "public"... :/ Perhaps best
to just change back to returning the useless int32.

+      int transport_overhead_per_packet_byte) = 0;
 
   // Returns max payload length, which is a combination of the configuration
   // MaxTransferUnit and TransportOverhead.