IncomingPacket(const uint8_t*, size_t) is used as entry point instead
of IncomingRTCPPacket(PacketInformation* out, RtcpParser* in);
Result is validated by checking which callbacks were called instead
of checking intermediate structure PacketInformaion.
This allows to switch parsing implementation.
BUG=webrtc:5260
Review-Url: https://codereview.webrtc.org/2292093002
Cr-Commit-Position: refs/heads/master@{#14074}
1e714ae7a6