Deprecated avcodec_decode_video2 is replaced with
avcodec_send_packet and avcodec_receive_frame.
https://www.ffmpeg.org/doxygen/3.1/group__lavc__encdec.html
Setting av_context_->refcounted_frames=1 is removed. This
is automatically enabled if avcodec_receive_frame us used.
Bug: webrtc:8493
Change-Id: Id1d2b1315717f4553fb7fc182197f9429bd31daf
Reviewed-on: https://webrtc-review.googlesource.com/18462
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20601}