Reduce synchronization in the class significantly and not hold a lock
while calling out to external implementations.
* Rewrite tests to use a real ProcessThread.
* Update some code to use C++ 11 constructs & library features.
Bug: webrtc:9064
Change-Id: I240a819efb6ef8197da3f2edf7acf068d2a27e8b
Reviewed-on: https://webrtc-review.googlesource.com/64521
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22649}
38c5d9345d