Reason for revert: Breaks fuzzer compilation. Original issue's description: > Make rtcp parsing implementation private in RtcpReceiver: > Function just for Parse and for Callbacks moved to private section. > All handles moved from protected to private section. > > BUG=webrtc:5260 > R=sprang@webrtc.org > > Committed: https://crrev.com/faf708e238c7b43a732fbebf79ac9298b4b95a95 > Cr-Commit-Position: refs/heads/master@{#14181} TBR=sprang@webrtc.org # Skipping CQ checks because original CL landed less than 1 days ago. NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true BUG=webrtc:5260 Review-Url: https://codereview.webrtc.org/2332673003 Cr-Commit-Position: refs/heads/master@{#14182}