Use RtcpPacket to send XR (RTRR, DLRR, VOIP) in RtcpSender

BUG=webrtc:2450
R=asapersson@webrtc.org

Review URL: https://codereview.webrtc.org/1304123003 .

Cr-Commit-Position: refs/heads/master@{#9820}
1 file changed