Remove MessageLoop::current() from history_service.cc

Remove MessageLoop::current() from history_service.cc

Whenever possible, use Thread/SequencedTaskRunnerHandle::Get() instead
of MessageLoop::current(). Thread/SequencedTaskRunnerHandle::Get() work
within TaskScheduler while MessageLoop::current() doesn't.

Good reasons to use MessageLoop::current():
- Add destruction, nesting or task observers.
- Run nested loops.

Bad reasons to use MessageLoop::current():
- Post tasks. Use Thread/SequencedTaskRunnerHandle::Get() instead.
- Watch a file descriptor. Use FileDescriptorWatcher instead.
- Verify that it is possible to post tasks to the current thread.
  Use Thread/SequencedTaskRunnerHandle::IsSet() instead.
- Verify that code runs on a specific thread. Use
  SingleThreadTaskRunner::BelongsToCurrentThread() instead.

BUG=650723
Committed: https://crrev.com/571fada22bd532cb22a98ff61092026826deb98b
Cr-Commit-Position: refs/heads/master@{#425121}

[fdoray, 2016-10-11 18:28:21]

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

[commit-bot: I haz the power, 2016-10-11 18:28:37]

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, 2016-10-11 18:41:56]

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

[commit-bot: I haz the power, 2016-10-11 18:41:57]

Dry run: Try jobs failed on following builders:
  ios-device on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)

[fdoray, 2016-10-12 17:05:09]

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

[commit-bot: I haz the power, 2016-10-12 17:05:41]

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, 2016-10-12 17:54:24]

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

[commit-bot: I haz the power, 2016-10-12 17:54:25]

Dry run: This issue passed the CQ dry run.

[fdoray, 2016-10-12 20:02:00]

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

[fdoray, 2016-10-12 20:02:01]

PTAL

[sdefresne, 2016-10-13 17:25:35]

lgtm

https://codereview.chromium.org/2406423003/diff/20001/components/history/core...
File components/history/core/browser/history_backend.h (right):

https://codereview.chromium.org/2406423003/diff/20001/components/history/core...
components/history/core/browser/history_backend.h:44: class MessageLoop;
I think you can remove this line.

[fdoray, 2016-10-13 18:24:42]

The CQ bit was checked by fdoray@chromium.org

[fdoray, 2016-10-13 18:24:42]

The patchset sent to the CQ was uploaded after l-g-t-m from
sdefresne@chromium.org
Link to the patchset: https://codereview.chromium.org/2406423003/#ps40001
(title: "CR sdefresne #11")

[commit-bot: I haz the power, 2016-10-13 18:25:24]

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

[fdoray, 2016-10-13 18:30:27]

https://codereview.chromium.org/2406423003/diff/20001/components/history/core...
File components/history/core/browser/history_backend.h (right):

https://codereview.chromium.org/2406423003/diff/20001/components/history/core...
components/history/core/browser/history_backend.h:44: class MessageLoop;
On 2016/10/13 17:25:35, sdefresne wrote:
> I think you can remove this line.

Done.

[commit-bot: I haz the power, 2016-10-13 19:15:54]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-10-13 19:17:42]

Description was changed from

==========
Remove MessageLoop::current() from history_service.cc

Whenever possible, use Thread/SequencedTaskRunnerHandle::Get() instead
of MessageLoop::current(). Thread/SequencedTaskRunnerHandle::Get() work
within TaskScheduler while MessageLoop::current() doesn't.

Good reasons to use MessageLoop::current():
- Add destruction, nesting or task observers.
- Run nested loops.

Bad reasons to use MessageLoop::current():
- Post tasks. Use Thread/SequencedTaskRunnerHandle::Get() instead.
- Watch a file descriptor. Use FileDescriptorWatcher instead.
- Verify that it is possible to post tasks to the current thread.
  Use Thread/SequencedTaskRunnerHandle::IsSet() instead.
- Verify that code runs on a specific thread. Use
  SingleThreadTaskRunner::BelongsToCurrentThread() instead.

BUG=650723
==========

to

==========
Remove MessageLoop::current() from history_service.cc

Whenever possible, use Thread/SequencedTaskRunnerHandle::Get() instead
of MessageLoop::current(). Thread/SequencedTaskRunnerHandle::Get() work
within TaskScheduler while MessageLoop::current() doesn't.

Good reasons to use MessageLoop::current():
- Add destruction, nesting or task observers.
- Run nested loops.

Bad reasons to use MessageLoop::current():
- Post tasks. Use Thread/SequencedTaskRunnerHandle::Get() instead.
- Watch a file descriptor. Use FileDescriptorWatcher instead.
- Verify that it is possible to post tasks to the current thread.
  Use Thread/SequencedTaskRunnerHandle::IsSet() instead.
- Verify that code runs on a specific thread. Use
  SingleThreadTaskRunner::BelongsToCurrentThread() instead.

BUG=650723

Committed: https://crrev.com/571fada22bd532cb22a98ff61092026826deb98b
Cr-Commit-Position: refs/heads/master@{#425121}
==========

[commit-bot: I haz the power, 2016-10-13 19:17:43]

Patchset 3 (id:??) landed as
https://crrev.com/571fada22bd532cb22a98ff61092026826deb98b
Cr-Commit-Position: refs/heads/master@{#425121}