Revert of Remove race in DeclarativeContentApiTest.RulesPersistence test (patchset #1 id:1 of https://codereview.chromium.org/
1222193006/)
Reason for revert:
Breaks linux clang tot bot (https://crbug.com/512506) and causes flakiness on Vista Tests bot (https://crbug.com/512431).
BUG=512506, 512431
Original issue's description:
> Remove race in DeclarativeContentApiTest.RulesPersistence test
>
> BUG=
>
> Committed: https://crrev.com/
28218513bf9580515b03c73ab786c27844e9b40b
> Cr-Commit-Position: refs/heads/master@{#339432}
TBR=battre@chromium.org,matthewtff@yandex-team.ru
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=
Review URL: https://codereview.chromium.org/
1247743004
Cr-Commit-Position: refs/heads/master@{#339713}