Reason for revert:
Reverting this as it had no effect.
Original issue's description:
> Don't set the priority of the decoder to 'high' on Android.
> Doing so competes with the actual decoding that happens on a different thread.
>
> BUG=695438
>
> Review-Url: https://codereview.webrtc.org/2745813003
> Cr-Commit-Position: refs/heads/master@{#17184}
> Committed: ca37cf6691TBR=stefan@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=695438
Review-Url: https://codereview.webrtc.org/2757733005
Cr-Commit-Position: refs/heads/master@{#17297}