Remove MessageLoop::current() from url_request.cc.

Remove MessageLoop::current() from url_request.cc.

Whenever possible, use ThreadTaskRunnerHandle::Get() instead of
MessageLoop::current(). ThreadTaskRunnerHandle::Get() works 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 ThreadTaskRunnerHandle::Get() instead.
- Watch a file descriptor. Use FileDescriptorWatcher instead.
- Verify that it is possible to post tasks to the current thread.
  Use ThreadTaskRunnerHandle::IsSet() instead.
- Verify that code runs on a specific thread. Use
  SingleThreadTaskRunner::BelongsToCurrentThread() instead.

BUG=650723
Committed: https://crrev.com/1c6a29c14bcff7c8a8d2e6178ea684d50d82558b
Cr-Commit-Position: refs/heads/master@{#425151}

[fdoray, 2016-10-11 16:20:25]

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

[commit-bot: I haz the power, 2016-10-11 16:20:37]

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

[fdoray, 2016-10-11 17:12:19]

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

[fdoray, 2016-10-11 17:12:20]

PTAL

[commit-bot: I haz the power, 2016-10-11 17:15:16]

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

[commit-bot: I haz the power, 2016-10-11 17:15:17]

Dry run: This issue passed the CQ dry run.

[gavinp, 2016-10-13 20:10:17]

The CQ bit was checked by gavinp@chromium.org

[gavinp, 2016-10-13 20:10:17]

lgtm

[commit-bot: I haz the power, 2016-10-13 20:10:32]

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, 2016-10-13 21:04:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-13 21:06:24]

Description was changed from

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

Whenever possible, use ThreadTaskRunnerHandle::Get() instead of
MessageLoop::current(). ThreadTaskRunnerHandle::Get() works 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 ThreadTaskRunnerHandle::Get() instead.
- Watch a file descriptor. Use FileDescriptorWatcher instead.
- Verify that it is possible to post tasks to the current thread.
  Use ThreadTaskRunnerHandle::IsSet() instead.
- Verify that code runs on a specific thread. Use
  SingleThreadTaskRunner::BelongsToCurrentThread() instead.

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

to

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

Whenever possible, use ThreadTaskRunnerHandle::Get() instead of
MessageLoop::current(). ThreadTaskRunnerHandle::Get() works 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 ThreadTaskRunnerHandle::Get() instead.
- Watch a file descriptor. Use FileDescriptorWatcher instead.
- Verify that it is possible to post tasks to the current thread.
  Use ThreadTaskRunnerHandle::IsSet() instead.
- Verify that code runs on a specific thread. Use
  SingleThreadTaskRunner::BelongsToCurrentThread() instead.

BUG=650723

Committed: https://crrev.com/1c6a29c14bcff7c8a8d2e6178ea684d50d82558b
Cr-Commit-Position: refs/heads/master@{#425151}
==========

[commit-bot: I haz the power, 2016-10-13 21:06:24]

Patchset 1 (id:??) landed as
https://crrev.com/1c6a29c14bcff7c8a8d2e6178ea684d50d82558b
Cr-Commit-Position: refs/heads/master@{#425151}