Added accessor and Parse function removed dependencies on structures from rtcp_utility.h (except RtcpCommonHeader) BUG=webrtc:5260 R=åsapersson Review URL: https://codereview.webrtc.org/1675583002 Cr-Commit-Position: refs/heads/master@{#11502}
BUG=webrtc:5260 R=åsapersson Review URL: https://codereview.webrtc.org/1575023002 Cr-Commit-Position: refs/heads/master@{#11206}