Make rtcp sender use max transfer unit.

webrtc/modules/rtp_rtcp/source/rtcp_sender.h

Index: webrtc/modules/rtp_rtcp/source/rtcp_sender.h
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_sender.h b/webrtc/modules/rtp_rtcp/source/rtcp_sender.h
index 5183b56b9ff97490a3df76cffcaf506de1ab49d6..ba6fb7005581fb24d217b4dee738e8d7bd6a9014 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_sender.h
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_sender.h
@@ -132,6 +132,8 @@ class RTCPSender {
 
   void SetTMMBRStatus(bool enable);
 
+  void SetMaxPayloadLength(size_t max_payload_length);
+
   int32_t SetTMMBN(const TMMBRSet* boundingSet);
 
   int32_t SetApplicationSpecificData(uint8_t subType,
@@ -240,6 +242,7 @@ class RTCPSender {
   TMMBRHelp tmmbr_help_ GUARDED_BY(critical_section_rtcp_sender_);
   uint32_t tmmbr_send_ GUARDED_BY(critical_section_rtcp_sender_);
   uint32_t packet_oh_send_ GUARDED_BY(critical_section_rtcp_sender_);
+  size_t max_payload_length_;
 
   // APP
   uint8_t app_sub_type_ GUARDED_BY(critical_section_rtcp_sender_);