Flush TaskScheduler in ProfileBrowserTest.*.

Flush TaskScheduler in ProfileBrowserTest.*.

When the BrowserScheduler/RedirectHistoryService experiment is disabled,
HistoryService uses a dedicated thread for backend operations. This thread
is joined when the HistoryService is deleted.

When the BrowserScheduler/RedirectHistoryService experiment is enabled,
HistoryService uses a TaskScheduler sequence for backend operations.
These tasks can run after the HistoryService has been deleted.

History backend tasks access databases in the profile directory. A crash
occurs if these accesses occur after the profile directory has been deleted.
To prevent this from happening in ProfileBrowserTest.*., this CL adds code to
flush TaskScheduler before deleting the profile directory.

BUG=661143, 676714
Review-Url: https://codereview.chromium.org/2611053003
Cr-Commit-Position: refs/heads/master@{#441951}
Committed: https://chromium.googlesource.com/chromium/src/+/584e16efe96fd3b746987ac7afc357798f512921

[fdoray, 2017-01-05 19:34:27]

Description was changed from

==========
Flush TaskScheduler in ProfileBrowserTest.*.

This prevents HistoryBackend tasks from accessing databases after
the directory (base::ScopedTempDir) that contains them has been deleted.

BUG=661143, 676714
==========

to

==========
Flush TaskScheduler in ProfileBrowserTest.*.

When the BrowserScheduler/RedirectHistoryService experiment is disabled,
HistoryService uses a dedicated thread for backend operations. This thread
is joined when the HistoryService is deleted.

When the BrowserScheduler/RedirectHistoryService experiment is enabled,
HistoryService uses a TaskScheduler sequence for backend operations.
These tasks can run after the HistoryService has been deleted.

History backend tasks access databases in the profile directory. A crash
occurs if these accesses occur after the profile directory has been deleted.
To prevent this from happening in ProfileBrowserTest.*., this CL adds code to
flush TaskScheduler before deleting the profile directory.

BUG=661143, 676714
==========

[fdoray, 2017-01-05 19:34:37]

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

[commit-bot: I haz the power, 2017-01-05 19:34:58]

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

[fdoray, 2017-01-05 19:35:03]

fdoray@chromium.org changed reviewers:
+ gab@chromium.org, robliao@chromium.org

[fdoray, 2017-01-05 19:35:03]

PTAL

[commit-bot: I haz the power, 2017-01-05 20:09:38]

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

[commit-bot: I haz the power, 2017-01-05 20:09:39]

Dry run: This issue passed the CQ dry run.

[gab, 2017-01-05 22:11:54]

lgtm, thanks

[fdoray, 2017-01-05 22:32:49]

fdoray@chromium.org changed reviewers:
+ anthonyvd@chromium.org

[fdoray, 2017-01-05 22:32:49]

anthonyvd@: PTAL

[robliao, 2017-01-06 02:33:17]

lgtm

[anthonyvd, 2017-01-06 16:48:06]

lgtm

[gab, 2017-01-06 16:48:22]

The CQ bit was checked by gab@chromium.org

[commit-bot: I haz the power, 2017-01-06 16:48:53]

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, 2017-01-06 16:53:41]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1483721302294300, "parent_rev":
"ed8dccd0c958bb372c8f266631e71a471a5b6c17", "commit_rev":
"584e16efe96fd3b746987ac7afc357798f512921"}

[commit-bot: I haz the power, 2017-01-06 16:54:09]

Description was changed from

==========
Flush TaskScheduler in ProfileBrowserTest.*.

When the BrowserScheduler/RedirectHistoryService experiment is disabled,
HistoryService uses a dedicated thread for backend operations. This thread
is joined when the HistoryService is deleted.

When the BrowserScheduler/RedirectHistoryService experiment is enabled,
HistoryService uses a TaskScheduler sequence for backend operations.
These tasks can run after the HistoryService has been deleted.

History backend tasks access databases in the profile directory. A crash
occurs if these accesses occur after the profile directory has been deleted.
To prevent this from happening in ProfileBrowserTest.*., this CL adds code to
flush TaskScheduler before deleting the profile directory.

BUG=661143, 676714
==========

to

==========
Flush TaskScheduler in ProfileBrowserTest.*.

When the BrowserScheduler/RedirectHistoryService experiment is disabled,
HistoryService uses a dedicated thread for backend operations. This thread
is joined when the HistoryService is deleted.

When the BrowserScheduler/RedirectHistoryService experiment is enabled,
HistoryService uses a TaskScheduler sequence for backend operations.
These tasks can run after the HistoryService has been deleted.

History backend tasks access databases in the profile directory. A crash
occurs if these accesses occur after the profile directory has been deleted.
To prevent this from happening in ProfileBrowserTest.*., this CL adds code to
flush TaskScheduler before deleting the profile directory.

BUG=661143, 676714

Review-Url: https://codereview.chromium.org/2611053003
Cr-Commit-Position: refs/heads/master@{#441951}
Committed:
https://chromium.googlesource.com/chromium/src/+/584e16efe96fd3b746987ac7afc3...
==========

[commit-bot: I haz the power, 2017-01-06 16:54:10]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/584e16efe96fd3b746987ac7afc3...