Migrate webrtc TaskQueue implementation to webrtc::TaskQueueBase interface

Bug: webrtc:10191
Change-Id: Iabedcad5e53f47e87bf289a2b09bc567bf7731ae
Reviewed-on: https://chromium-review.googlesource.com/c/1426788
Reviewed-by: Tommi <tommi@chromium.org>
Reviewed-by: Per Kjellander <perkj@chromium.org>
Commit-Queue: Tommi <tommi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#633287}
7 files changed