Do not run a nested loop in content::DeferredQuitRunLoop.

Do not run a nested loop in content::DeferredQuitRunLoop.

In preparation for the migration of BrowserThreads to
base/task_scheduler, we want to disallow running nested loops
on BrowserThreads (except IO and UI threads).
content::DeferredQuitRunLoop is currently the only code that
runs nested loops on these threads.

BUG=653916
Committed: https://crrev.com/8b65c3e37ffd93e7402d22cd053419a8a8edd862
Cr-Commit-Position: refs/heads/master@{#424534}

[fdoray, 2016-10-07 13:59:28]

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

[commit-bot: I haz the power, 2016-10-07 13:59:42]

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, 2016-10-07 14:41:04]

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

[commit-bot: I haz the power, 2016-10-07 14:41:05]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[fdoray, 2016-10-07 15:03:05]

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

[commit-bot: I haz the power, 2016-10-07 15:03:23]

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, 2016-10-07 15:43:39]

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

[commit-bot: I haz the power, 2016-10-07 15:43:40]

Dry run: This issue passed the CQ dry run.

[fdoray, 2016-10-07 15:47:48]

Description was changed from

==========
Do not run a nested loop in content::DeferredQuitRunLoop.

BUG=
==========

to

==========
Do not run a nested loop in content::DeferredQuitRunLoop.

In preparation for the migration of BrowserThreads to
base/task_scheduler, we want to disallow running nested loops
on BrowserThreads (except IO and UI threads).
content::DeferredQuitRunLoop is currently the only code that
runs nested loops on these threads.

BUG=653916
==========

[fdoray, 2016-10-07 15:48:25]

fdoray@chromium.org changed reviewers:
+ phajdan.jr@chromium.org

[fdoray, 2016-10-07 15:48:26]

PTAL

[Paweł Hajdan Jr., 2016-10-11 18:26:22]

phajdan.jr@chromium.org changed reviewers:
+ jam@chromium.org

[Paweł Hajdan Jr., 2016-10-11 18:26:22]

I'd be more comfortable with John reviewing this code.

FWIW it looks OK to me at a glance, but I know message loops are tricky. I might
learn something here.

John, if there are other reviewers I should be adding in cases like this to
better distribute the load, just let me know.

[jam, 2016-10-11 19:24:19]

lgtm

btw when do we run nested message loops on IO thread?

[fdoray, 2016-10-11 19:35:55]

On 2016/10/11 19:24:19, jam wrote:
> lgtm
> 
> btw when do we run nested message loops on IO thread?

We don't need to disallow running nested message loops on IO thread because we
don't plan to migrate it to TaskScheduler anytime soon. I don't know if we ever
ru nested message loop on IO thread. Do you think it should be disallowed?

[fdoray, 2016-10-11 19:36:08]

The CQ bit was checked by fdoray@chromium.org

[commit-bot: I haz the power, 2016-10-11 19:36:40]

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 20:37:57]

Description was changed from

==========
Do not run a nested loop in content::DeferredQuitRunLoop.

In preparation for the migration of BrowserThreads to
base/task_scheduler, we want to disallow running nested loops
on BrowserThreads (except IO and UI threads).
content::DeferredQuitRunLoop is currently the only code that
runs nested loops on these threads.

BUG=653916
==========

to

==========
Do not run a nested loop in content::DeferredQuitRunLoop.

In preparation for the migration of BrowserThreads to
base/task_scheduler, we want to disallow running nested loops
on BrowserThreads (except IO and UI threads).
content::DeferredQuitRunLoop is currently the only code that
runs nested loops on these threads.

BUG=653916
==========

[commit-bot: I haz the power, 2016-10-11 20:37:58]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-10-11 20:41:18]

Description was changed from

==========
Do not run a nested loop in content::DeferredQuitRunLoop.

In preparation for the migration of BrowserThreads to
base/task_scheduler, we want to disallow running nested loops
on BrowserThreads (except IO and UI threads).
content::DeferredQuitRunLoop is currently the only code that
runs nested loops on these threads.

BUG=653916
==========

to

==========
Do not run a nested loop in content::DeferredQuitRunLoop.

In preparation for the migration of BrowserThreads to
base/task_scheduler, we want to disallow running nested loops
on BrowserThreads (except IO and UI threads).
content::DeferredQuitRunLoop is currently the only code that
runs nested loops on these threads.

BUG=653916

Committed: https://crrev.com/8b65c3e37ffd93e7402d22cd053419a8a8edd862
Cr-Commit-Position: refs/heads/master@{#424534}
==========

[commit-bot: I haz the power, 2016-10-11 20:41:19]

Patchset 3 (id:??) landed as
https://crrev.com/8b65c3e37ffd93e7402d22cd053419a8a8edd862
Cr-Commit-Position: refs/heads/master@{#424534}

[jam, 2016-10-11 21:23:49]

On 2016/10/11 19:35:55, fdoray wrote:
> On 2016/10/11 19:24:19, jam wrote:
> > lgtm
> > 
> > btw when do we run nested message loops on IO thread?
> 
> We don't need to disallow running nested message loops on IO thread because we
> don't plan to migrate it to TaskScheduler anytime soon. I don't know if we
ever
> ru nested message loop on IO thread. Do you think it should be disallowed?

I don't know of an instance (but not saying there aren't, but I would be very
surprised). I asked because the cl description said that the IO thread runs
nested loops.