base: Enable SequenceManager backend in MessageLoop by default

Make the MessageLoop to use SequenceManager as its default backend. Note
that we are also launching a separate Finch trial to evaluate the
performance and stability of the SequenceManager relative to
MessageLoopImpl.

Bug: 891670
Change-Id: If968033bbbbda0037dae2c2715f3827a13afcdc8
Reviewed-on: https://chromium-review.googlesource.com/c/1379763
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#626054}
1 file changed