commit 2475ae2e4cdbb7cbfa2a4801cbc36ff7eb73aacd
author magjed <magjed@webrtc.org> Tue Sep 12 04:42:15 2017 -0700
committer Commit Bot <commit-bot@chromium.org> Tue Sep 12 11:42:15 2017 +0000
tree 88c1c5edc4de9f592a83d5eacb68f1dac4bd2882
parent 1e7dd31001cfa13b066e27352a24947c5ff95c31

Simplify passing video coded factories in media engine

We soon want to be able to pass in a new type of video codec factories,
see issue 7925 for more information. We currently plumb these video
codec factories in a clumsy way from the media engine to the video
engine, which will require us to update a lot of places when we add
new video codec factory types. This CL cleans up the way we pass in
video codec factories to make it easier to add the new factory types.

In particular, this CL:
 * Updates WebRtcVideoEngine to take the video codec factories as
   arguments in ctor instead of in SetExternalVideoCodec functions.
 * Remove the Init() function from the vidoe engines - this function is
   not used.
 * Update CompositeMediaEngine to take generic variadic arguments, so we
   can send different arguments for different engines, without having to
   update this class.
 * Simplify ownership of video codec factories in WebRtcVideoEngine.
   WebRtcVideoEngine outlives WebRtcVideoChannel,
   WebRtcVideoSendStream and WebRtcVideoReceiveStream, so it can
   keep ownership without having to share ownership with these classes.

BUG=webrtc:7925

Review-Url: https://codereview.webrtc.org/3008043002
Cr-Commit-Position: refs/heads/master@{#19794}