Fix tsan deadlock in base_unittest

Fix tsan deadlock in base_unittest

BUG=672859
Committed: https://crrev.com/5d5b6f22db0d049c4300e06b7a16b4bde514bcdd
Cr-Commit-Position: refs/heads/master@{#437623}

[lawrencewu, 2016-12-09 17:04:59]

lawrencewu@chromium.org changed reviewers:
+ asvitkine@chromium.org

[lawrencewu, 2016-12-09 17:06:08]

lawrencewu@chromium.org changed reviewers:
+ gab@chromium.org

[Alexei Svitkine (slow), 2016-12-09 17:24:57]

lgtm

[lawrencewu, 2016-12-09 17:26:10]

The CQ bit was checked by lawrencewu@chromium.org

[commit-bot: I haz the power, 2016-12-09 17:26:31]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-09 20:28:27]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1481304370925630, "parent_rev":
"5de6ef6778c0b342fe603b5d3735bc110167264c", "commit_rev":
"9e6eeaf2213596fb48688f89830dfaeda968ba15"}

[commit-bot: I haz the power, 2016-12-09 20:28:53]

Description was changed from

==========
Fix tsan deadlock in base_unittest

BUG=672859
==========

to

==========
Fix tsan deadlock in base_unittest

BUG=672859

Review-Url: https://codereview.chromium.org/2568533002
==========

[commit-bot: I haz the power, 2016-12-09 20:28:54]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-12 14:37:21]

Description was changed from

==========
Fix tsan deadlock in base_unittest

BUG=672859

Review-Url: https://codereview.chromium.org/2568533002
==========

to

==========
Fix tsan deadlock in base_unittest

BUG=672859

Committed: https://crrev.com/5d5b6f22db0d049c4300e06b7a16b4bde514bcdd
Cr-Commit-Position: refs/heads/master@{#437623}
==========

[commit-bot: I haz the power, 2016-12-12 14:37:22]

Patchset 1 (id:??) landed as
https://crrev.com/5d5b6f22db0d049c4300e06b7a16b4bde514bcdd
Cr-Commit-Position: refs/heads/master@{#437623}