[base] Move TaskAnnotator to base/task.

Move TaskAnnotator out of base::debug namespace (as is also runs tasks,
which can be useful not only for debug but also in some other cases).

Move it to base/task/common to other task posting and running
infrastructure.

R=gab@chromium.org
TBR=gab@chromium.org

Change-Id: Ia464c7476f9d8342f417f364fb2a66a87899b02b
Reviewed-on: https://chromium-review.googlesource.com/c/1477894
Commit-Queue: Alexander Timin <altimin@chromium.org>
Reviewed-by: Fran├žois Doray <fdoray@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#633717}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 91795ee2f4119b94132369092771473b98475713
1 file changed