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

Remove MessageLoop::current() from rendering_helper.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/9d97226d3b06bd96e376f6ab6975089a4744b7a7
Cr-Commit-Position: refs/heads/master@{#424497}

[fdoray, 2016-10-11 16:32:19]

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

[commit-bot: I haz the power, 2016-10-11 16:32:42]

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 16:40:50]

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

[commit-bot: I haz the power, 2016-10-11 16:40:51]

Dry run: Try jobs failed on following builders:
  chromeos_amd64-generic_chromium_compile_only_ng on
master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_amd64-...)

[fdoray, 2016-10-11 17:14:27]

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

[commit-bot: I haz the power, 2016-10-11 17:14:55]

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, 2016-10-11 18:28:43]

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

[commit-bot: I haz the power, 2016-10-11 18:28:44]

Dry run: This issue passed the CQ dry run.

[fdoray, 2016-10-11 18:33:43]

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

[fdoray, 2016-10-11 18:33:44]

PTAL

[sandersd (OOO until July 31), 2016-10-11 18:35:17]

lgtm

[fdoray, 2016-10-11 18:35:39]

The CQ bit was checked by fdoray@chromium.org

[commit-bot: I haz the power, 2016-10-11 18:36:01]

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 18:49:18]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-10-11 18:51:32]

Description was changed from

==========
Remove MessageLoop::current() from rendering_helper.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 rendering_helper.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/9d97226d3b06bd96e376f6ab6975089a4744b7a7
Cr-Commit-Position: refs/heads/master@{#424497}
==========

[commit-bot: I haz the power, 2016-10-11 18:51:33]

Patchset 2 (id:??) landed as
https://crrev.com/9d97226d3b06bd96e376f6ab6975089a4744b7a7
Cr-Commit-Position: refs/heads/master@{#424497}