commit c06b133b2907ea67f2c1f23488a51e0de643e9ef
author tommi <tommi@webrtc.org> Sat May 14 18:31:40 2016
committer Commit bot <commit-bot@chromium.org> Sat May 14 18:31:49 2016
tree aa3705793d642d53a97f6925114407a0dc5ca1f0
parent 353ca7610b64d17108a77be7262e571fdd41c2c4

Reland of New task queueing primitive for async tasks: TaskQueue.

New task queueing primitive for async tasks: TaskQueue.
TaskQueue is a new way to asynchronously execute tasks sequentially
in a thread safe manner with minimal locking.  The implementation
uses OS supported APIs to do this that are compatible with async IO
notifications from things like sockets and files.
This class is a part of rtc_base_approved, so can be used by both
the webrtc and libjingle parts of the WebRTC library.  Moving forward,
we can replace rtc::Thread and webrtc::ProcessThread with this implementation.
NOTE: It should not be assumed that all tasks that execute on a TaskQueue,
run on the same thread.  E.g. on Mac and iOS, we use GCD dispatch queues
which means that tasks might execute on different threads depending on
what's the most efficient thing to do.

TBR=perkj@webrtc.org,phoglund@webrtc.org

Review-Url: https://codereview.webrtc.org/1984503002
Cr-Commit-Position: refs/heads/master@{#12749}