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

Revert of Use TaskScheduler instead of blocking pool in supervised_user_url_filter.cc. (patchset #1 id:1 of https://codereview.chromium.org/2837943002/ )

Reason for revert:
SupervisedUserURLFilterTest tests are failing.

See:
https://uberchromegw.corp.google.com/i/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%281%29/builds/37642

Original issue's description:
> Use TaskScheduler instead of blocking pool in supervised_user_url_filter.cc.
> 
> The blocking pool is being deprecated in favor of TaskScheduler.
> 
> BUG=667892
> R=bauerb@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2837943002
> Cr-Commit-Position: refs/heads/master@{#466982}
> Committed: https://chromium.googlesource.com/chromium/src/+/47eaa2f4ade5724ed7bdbbd736579ae48702b9aa

TBR=bauerb@chromium.org,fdoray@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=667892
Review-Url: https://codereview.chromium.org/2836333002
Cr-Commit-Position: refs/heads/master@{#467016}
Committed: https://chromium.googlesource.com/chromium/src/+/c8aaea4fc06896f27d1d292ed16ed627b60d7fa2

[hcarmona, 2017-04-25 16:42:33]

The CQ bit was checked by hcarmona@chromium.org

[hcarmona, 2017-04-25 16:42:33]

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

[commit-bot: I haz the power, 2017-04-25 16:43:06]

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, 2017-04-25 16:43:32]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493138553391810, "parent_rev":
"5900ad5e7b93d988963d654cfa777b5d0477a1d9", "commit_rev":
"c8aaea4fc06896f27d1d292ed16ed627b60d7fa2"}

[commit-bot: I haz the power, 2017-04-25 16:43:46]

Description was changed from

==========
Revert of Use TaskScheduler instead of blocking pool in
supervised_user_url_filter.cc. (patchset #1 id:1 of
https://codereview.chromium.org/2837943002/ )

Reason for revert:
SupervisedUserURLFilterTest tests are failing.

See:
https://uberchromegw.corp.google.com/i/chromium.chromiumos/builders/Linux%20C...

Original issue's description:
> Use TaskScheduler instead of blocking pool in supervised_user_url_filter.cc.
> 
> The blocking pool is being deprecated in favor of TaskScheduler.
> 
> BUG=667892
> R=bauerb@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2837943002
> Cr-Commit-Position: refs/heads/master@{#466982}
> Committed:
https://chromium.googlesource.com/chromium/src/+/47eaa2f4ade5724ed7bdbbd73657...

TBR=bauerb@chromium.org,fdoray@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=667892
==========

to

==========
Revert of Use TaskScheduler instead of blocking pool in
supervised_user_url_filter.cc. (patchset #1 id:1 of
https://codereview.chromium.org/2837943002/ )

Reason for revert:
SupervisedUserURLFilterTest tests are failing.

See:
https://uberchromegw.corp.google.com/i/chromium.chromiumos/builders/Linux%20C...

Original issue's description:
> Use TaskScheduler instead of blocking pool in supervised_user_url_filter.cc.
> 
> The blocking pool is being deprecated in favor of TaskScheduler.
> 
> BUG=667892
> R=bauerb@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2837943002
> Cr-Commit-Position: refs/heads/master@{#466982}
> Committed:
https://chromium.googlesource.com/chromium/src/+/47eaa2f4ade5724ed7bdbbd73657...

TBR=bauerb@chromium.org,fdoray@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=667892

Review-Url: https://codereview.chromium.org/2836333002
Cr-Commit-Position: refs/heads/master@{#467016}
Committed:
https://chromium.googlesource.com/chromium/src/+/c8aaea4fc06896f27d1d292ed16e...
==========

[commit-bot: I haz the power, 2017-04-25 16:43:49]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/c8aaea4fc06896f27d1d292ed16e...

[Bernhard Bauer, 2017-04-25 16:57:56]

Hm... it looks like the SupervisedUserURLFilter is a member of the test fixture,
so is it possible that it's constructed before the TaskScheduler has been
initialized? When does that usually happen?