Revert of Use TaskScheduler instead of blocking pool in quota_policy_cookie_store.cc.

Revert of Use TaskScheduler instead of blocking pool in quota_policy_cookie_store.cc. (patchset #1 id:1 of https://codereview.chromium.org/2841683002/ )

Reason for revert:
This looks to have broken RestartTest.PRE_LocalStorageClearedOnExit.  Creating a revert now so I don't forget, but I'll CQ it Monday or Tuesday if I don't hear back about it.

Original issue's description:
> Use TaskScheduler instead of blocking pool in quota_policy_cookie_store.cc.
> 
> The blocking pool is being deprecated in favor of TaskScheduler.
> 
> BUG=667892
> R=boliu@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2841683002
> Cr-Commit-Position: refs/heads/master@{#466725}
> Committed: https://chromium.googlesource.com/chromium/src/+/8243c7c934eeb76043b9f6fa72c2e92b263b9b07

TBR=boliu@chromium.org,fdoray@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667892

[mmenke, 2017-05-05 19:24:57]

Created Revert of Use TaskScheduler instead of blocking pool in
quota_policy_cookie_store.cc.

[mmenke, 2017-05-05 19:25:09]

The CQ bit was checked by mmenke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-05 19:25:55]

Dry run: 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, 2017-05-05 19:29:53]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-05 19:29:54]

Dry run: Try jobs failed on following builders:
  android_n5x_swarming_rel on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_n5x_...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[mmenke, 2017-05-08 16:51:19]

Description was changed from

==========
Revert of Use TaskScheduler instead of blocking pool in
quota_policy_cookie_store.cc. (patchset #1 id:1 of
https://codereview.chromium.org/2841683002/ )

Reason for revert:
This looks to have broken RestartTest.PRE_LocalStorageClearedOnExit.  Creating a
revert now so I don't forget, but I'll CQ it Monday or Tuesday if I don't hear
back about it.

Original issue's description:
> Use TaskScheduler instead of blocking pool in quota_policy_cookie_store.cc.
> 
> The blocking pool is being deprecated in favor of TaskScheduler.
> 
> BUG=667892
> R=boliu@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2841683002
> Cr-Commit-Position: refs/heads/master@{#466725}
> Committed:
https://chromium.googlesource.com/chromium/src/+/8243c7c934eeb76043b9f6fa72c2...

TBR=boliu@chromium.org,fdoray@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667892
==========

to

==========
Revert of Use TaskScheduler instead of blocking pool in
quota_policy_cookie_store.cc. (patchset #1 id:1 of
https://codereview.chromium.org/2841683002/ )

Reason for revert:
This looks to have broken RestartTest.PRE_LocalStorageClearedOnExit.  Creating a
revert now so I don't forget, but I'll CQ it Monday or Tuesday if I don't hear
back about it.

Original issue's description:
> Use TaskScheduler instead of blocking pool in quota_policy_cookie_store.cc.
> 
> The blocking pool is being deprecated in favor of TaskScheduler.
> 
> BUG=667892
> R=boliu@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2841683002
> Cr-Commit-Position: refs/heads/master@{#466725}
> Committed:
https://chromium.googlesource.com/chromium/src/+/8243c7c934eeb76043b9f6fa72c2...

TBR=boliu@chromium.org,fdoray@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667892
==========