Use TaskScheduler instead of blocking pool in platform_util_linux.cc.

Use TaskScheduler instead of blocking pool in platform_util_linux.cc.

The blocking pool is being deprecated in favor of TaskScheduler.

BUG=667892
R=jochen@chromium.org

Review-Url: https://codereview.chromium.org/2674873003
Cr-Commit-Position: refs/heads/master@{#475593}
Committed: https://chromium.googlesource.com/chromium/src/+/4c386e823fb0576f66e5a79e7075c2f464a7b307

[fdoray, 2017-02-03 17:41:45]

Hi! I'm a Python script responsible for migrating tasks from the
blocking pool to TaskScheduler. In this CL, I used these traits to post to
TaskScheduler a task that was previously posted to the blocking pool:

.WithPriority(base::TaskPriority::BACKGROUND)
  User won't notice if the task takes an arbitrarily long time to complete.
  Making your task BACKGROUND allows non-BACKGROUND tasks to run faster :)

*No* .WithShutdownBehavior()

.MayBlock()
  The task may block. This includes but is not limited to tasks that wait on
  synchronous file I/O operations: read or write a file from disk, interact
  with a pipe or a socket, rename or delete a file, enumerate files in a
  directory, etc. This trait isn't required for the mere use of locks.

*No* .WithBaseSyncPrimitives()
  The task is not allowed to use these functions:
  - base::WaitableEvent::Wait
  - base::ConditionVariable::Wait
  - base::PlatformThread::Join
  - base::PlatformThread::Sleep
  - base::Process::WaitForExit
  - base::Process::WaitForExitWithTimeout

If you think this is correct, please LGTM and CQ this CL.

Otherwise, tell me which traits I should have used and I'll automatically
upload a new patch. You can find documentation at
https://cs.chromium.org/chromium/src/base/task_scheduler/task_traits.h

WithPriority()
[default/BACKGROUND/USER_VISIBLE/USER_BLOCKING]:

WithShutdownBehavior()
[default/CONTINUE_ON_SHUTDOWN/SKIP_ON_SHUTDOWN/BLOCK_SHUTDOWN]:

MayBlock()
[yes/no]:

WithBaseSyncPrimitives()
[yes/no]:

Comments for a human:
[A human will read this]

FAQ:

What should I do if the CQ dry run didn't pass?
You can ignore this CL. A human will take a look and get back to you.

Why are you doing this?
Browser threads, the blocking pool and base::WorkerPool are being deprecated
in favor of TaskScheduler. Design doc:
https://docs.google.com/document/d/1S2AAeoo1xa_vsLbDYBsDHCqhrkfiMgoIPlyRi6kxa...

What is the default priority?
A task posted to TaskScheduler without an explicit priority inherits its
priority from the calling context (e.g. a task posted to TaskScheduler
from a BACKGROUND task without an explicit .WithPriority() will have a
BACKGROUND priority).

What is the default shutdown behavior?
It is not documented on purpose. If your task shouldn't be skipped on shutdown
(e.g. a task that persists user data on disk), it should have an explicit
BLOCK_SHUTDOWN shutdown behavior. If it's important not to wait on your task
on shutdown (e.g. it takes a long time to run and could cause a shutdown
hang), it should have an explicit CONTINUE_ON_SHUTDOWN shutdown behavior.

[fdoray, 2017-02-03 17:41:46]

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

[commit-bot: I haz the power, 2017-02-03 17:42:03]

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, 2017-02-03 18:25:10]

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

[commit-bot: I haz the power, 2017-02-03 18:25:10]

Dry run: This issue passed the CQ dry run.

[jochen (gone - plz use gerrit), 2017-02-04 18:21:15]

it seems that CheckNautilusIsDefault ends up executing an external process and
waits for that process to terminate. Shouldn't that require base sync
primitives?

[fdoray, 2017-02-06 09:25:49]

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

[commit-bot: I haz the power, 2017-02-06 09:25:59]

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

[fdoray, 2017-02-06 09:26:11]

PTAnL

[jochen (gone - plz use gerrit), 2017-02-06 09:27:28]

lgtm

[fdoray, 2017-02-06 09:27:56]

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

[commit-bot: I haz the power, 2017-02-06 09:28:04]

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

[fdoray, 2017-02-06 09:29:11]

The CQ bit was unchecked by fdoray@chromium.org

[fdoray, 2017-02-06 09:29:12]

The CQ bit was checked by fdoray@chromium.org

[fdoray, 2017-02-06 09:29:13]

The patchset sent to the CQ was uploaded after l-g-t-m from jochen@chromium.org
Link to the patchset: https://codereview.chromium.org/2674873003/#ps60001
(title: "USER_BLOCKING")

[commit-bot: I haz the power, 2017-02-06 09:29:23]

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, 2017-02-06 10:22:24]

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

[commit-bot: I haz the power, 2017-02-06 10:22:24]

Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[fdoray, 2017-05-26 12:08:31]

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

[commit-bot: I haz the power, 2017-05-26 12:08:39]

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, 2017-05-26 12:10:29]

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

[commit-bot: I haz the power, 2017-05-26 12:10:30]

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...)
  ios-device-xcode-clang on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device-xcode-...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[fdoray, 2017-05-29 19:31:35]

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

[commit-bot: I haz the power, 2017-05-29 19:31:49]

Dry run: CQ is trying da patch.

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

[fdoray, 2017-05-29 19:33:24]

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

[commit-bot: I haz the power, 2017-05-29 19:33:32]

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, 2017-05-29 20:21:13]

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

[commit-bot: I haz the power, 2017-05-29 20:21:14]

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

[fdoray, 2017-05-30 15:42:02]

The CQ bit was checked by fdoray@chromium.org

[fdoray, 2017-05-30 15:42:02]

The patchset sent to the CQ was uploaded after l-g-t-m from jochen@chromium.org
Link to the patchset: https://codereview.chromium.org/2674873003/#ps120001
(title: "MayBlock()")

[commit-bot: I haz the power, 2017-05-30 15:42:26]

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, 2017-05-30 15:57:34]

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

[commit-bot: I haz the power, 2017-05-30 15:57:36]

Try jobs failed on following builders:
  linux_chromium_compile_dbg_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[fdoray, 2017-05-30 16:54:13]

The CQ bit was checked by fdoray@chromium.org

[fdoray, 2017-05-30 16:54:13]

The patchset sent to the CQ was uploaded after l-g-t-m from jochen@chromium.org
Link to the patchset: https://codereview.chromium.org/2674873003/#ps140001
(title: "fix build error")

[commit-bot: I haz the power, 2017-05-30 16:54:41]

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, 2017-05-30 18:00:17]

CQ is committing da patch.

Bot data: {"patchset_id": 140001, "attempt_start_ts": 1496163253008140,
"parent_rev": "28f9bbec79ad97de51c4e99bb13359e1d691add0", "commit_rev":
"4c386e823fb0576f66e5a79e7075c2f464a7b307"}

[commit-bot: I haz the power, 2017-05-30 18:00:26]

Description was changed from

==========
Use TaskScheduler instead of blocking pool in platform_util_linux.cc.

The blocking pool is being deprecated in favor of TaskScheduler.

BUG=667892
R=jochen@chromium.org
==========

to

==========
Use TaskScheduler instead of blocking pool in platform_util_linux.cc.

The blocking pool is being deprecated in favor of TaskScheduler.

BUG=667892
R=jochen@chromium.org

Review-Url: https://codereview.chromium.org/2674873003
Cr-Commit-Position: refs/heads/master@{#475593}
Committed:
https://chromium.googlesource.com/chromium/src/+/4c386e823fb0576f66e5a79e7075...
==========

[commit-bot: I haz the power, 2017-05-30 18:00:28]

Committed patchset #8 (id:140001) as
https://chromium.googlesource.com/chromium/src/+/4c386e823fb0576f66e5a79e7075...