Reason for revert:
Reverting while fixing build issue in Chromium.
Original issue's description:
> Use TaskQueue in IncomingVideoStream instead of the PlatformThread + event timer approach.
>
> BUG=webrtc:7219, webrtc:7253
>
> Review-Url: https://codereview.webrtc.org/2716473002
> Cr-Commit-Position: refs/heads/master@{#16860}
> Committed: e2d1d64295
TBR=mflodman@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7219, webrtc:7253
Review-Url: https://codereview.webrtc.org/2714393003
Cr-Commit-Position: refs/heads/master@{#16863}
Name: WebRTC URL: http://www.webrtc.org Version: 90 License: BSD License File: LICENSE Description: WebRTC provides real time voice and video processing functionality to enable the implementation of PeerConnection/MediaStream. Third party code used in this project is described in the file LICENSE_THIRD_PARTY.