This is a reland of 154ee1fd8547768a49b7d67ce586ef5d3c5d9ebc
Original change's description:
> Move ulpfec, red, and flexfec codec to video engine
>
> These codecs are currently being added in the internal encoder factory.
> This means that the new injectable video codec factories will miss them.
> This CL moves adding them into the video engine so that both factory
> types will get them.
>
> This CL makes a functional change in that RED, ULPFEC, and FlexFec will
> be placed after both the internal and external codecs. Previously,
> it was placed between the internal and external codecs.
>
> Bug: webrtc:8527
> Change-Id: I5aa7a3ca674f621b17cf3aa095a225c753488e09
> Reviewed-on: https://webrtc-review.googlesource.com/22964
> Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
> Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#20700}
TBR=brandt@webrtc.org
Bug: webrtc:8527
Change-Id: I79ced9a909fd424f1308d62e449268dcc9289538
Reviewed-on: https://webrtc-review.googlesource.com/24060
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20749}
9b16e2d354