Add callbacks for send channel rtcp statistics

BUG=2235
R=mflodman@webrtc.org, pbos@webrtc.org, stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/4429004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5220 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/rtp_rtcp/interface/rtp_rtcp.h

@@ -590,6 +590,12 @@ class RtpRtcp : public Module {
     // Returns true if the module is configured to store packets.
     virtual bool StorePackets() const = 0;
 
+    // Called on receipt of RTCP report block from remote side.
+    virtual void RegisterSendChannelRtcpStatisticsCallback(
+        RtcpStatisticsCallback* callback) = 0;
+    virtual RtcpStatisticsCallback*
+        GetSendChannelRtcpStatisticsCallback() = 0;
+
     /**************************************************************************
     *
     *   Audio