Revert "Adding injectable audio decoder and encoder factory support to the RTCPeerConnection obj-c layer."

This reverts commit 96de428fd1f301c3ad1355183b45e44db5ef3f7f.

Reason for revert: Gives compile errors because the new ObjC++ headers are included in some targets that use ObjC.

Original change's description:
> Adding injectable audio decoder and encoder factory support to the RTCPeerConnection obj-c layer.
> 
> Bug: webrtc:8093
> Change-Id: I868ce5f75a72c6deb065dec60784289d045ae22a
> Reviewed-on: https://chromium-review.googlesource.com/608981
> Commit-Queue: Jeremy Newton-Smith <jeremyns@webrtc.org>
> Reviewed-by: Zeke Chin <tkchin@webrtc.org>
> Reviewed-by: Kári Tristan Helgason <kthelgason@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#19477}

TBR=kjellander@webrtc.org,tkchin@webrtc.org,kthelgason@webrtc.org,jeremyns@webrtc.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: webrtc:8093
Change-Id: I3ade9dd979c9f13990a2972b15b786b8e78e1cd4
Reviewed-on: https://chromium-review.googlesource.com/640810
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Original-Commit-Position: refs/heads/master@{#19573}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: f83dc8bbe587442b33e322ff076933358f1a6f47
10 files changed