This CL converts the ForwardErrorCorrection class to use std::unique_ptr
for memory management, rather than manually delete'ing allocated memory.
It further renames some data structures and types to distinguish between
generated FEC packets (i.e. coming from the encode operation) and
received FEC packets (i.e. coming in over the wire, intended for the
decode operation).
BUG=webrtc:5654
Review-Url: https://codereview.webrtc.org/2099243003
Cr-Commit-Position: refs/heads/master@{#13687}