Revert of Fixed flakiness in PolicyTest.FileURLBlacklist.

Revert of Fixed flakiness in PolicyTest.FileURLBlacklist. (patchset #5 id:80001 of https://codereview.chromium.org/551323003/)

Reason for revert:
It's causing lots of flakiness on trybots, now that you added logging look at the past flakiness for more info:

http://chromium-try-flakes.appspot.com/search?q=PolicyTest.FileURLBlacklist

Original issue's description:
> Re-enabled PolicyTest.FileURLBlacklist.
>
> This test flakes on the Mac. This CL adds additional logging to help diagnose the source of flakiness.
>
> BUG=339240
>
> Committed: https://crrev.com/82405166f151d0d0be73d040aa5b77d309034aa0
> Cr-Commit-Position: refs/heads/master@{#295956}

TBR=pneubeck@chromium.org,joaodasilva@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=339240
Committed: https://crrev.com/d6be16e996debac76cdf70a85a3d4ea620b13dbb
Cr-Commit-Position: refs/heads/master@{#297127}

[jam, 2014-09-28 15:17:38]

Created Revert of Fixed flakiness in PolicyTest.FileURLBlacklist.

[commit-bot: I haz the power, 2014-09-28 15:18:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/608153002/1

[commit-bot: I haz the power, 2014-09-28 15:18:41]

Committed patchset #1 (id:1) as 197ae2ccbbaa979bb19139dcbb9d11fb8b4e1c98

[commit-bot: I haz the power, 2014-09-28 15:19:21]

Patchset 1 (id:??) landed as
https://crrev.com/d6be16e996debac76cdf70a85a3d4ea620b13dbb
Cr-Commit-Position: refs/heads/master@{#297127}