Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

TBR=jochen@chromium.org
BUG=659191
Committed: https://crrev.com/9e2697603c48a60c78ca99ad404251d2764ec9c2
Cr-Commit-Position: refs/heads/master@{#440200}

[fdoray, 2016-12-01 21:52:29]

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

[commit-bot: I haz the power, 2016-12-01 21:52:58]

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, 2016-12-01 22:05:48]

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

[commit-bot: I haz the power, 2016-12-01 22:05:49]

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, 2016-12-02 13:40:22]

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

[commit-bot: I haz the power, 2016-12-02 13:40:31]

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, 2016-12-02 14:23:51]

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

[commit-bot: I haz the power, 2016-12-02 14:23:52]

Dry run: This issue passed the CQ dry run.

[fdoray, 2016-12-02 19:27:49]

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

[fdoray, 2016-12-02 19:27:49]

Please review this CL. In particular, make sure that the traits mentioned in the
CL description make sense for this task. Thanks!


Note: WorkerPool is being deprecated in favor of TaskScheduler. Read the design
doc
https://docs.google.com/document/d/1S2AAeoo1xa_vsLbDYBsDHCqhrkfiMgoIPlyRi6kxa...


Note: On shutdown, WorkerPool does not wait for tasks to run. To get the same
behavior in TaskScheduler, we used TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN.

[jochen (gone - plz use gerrit), 2016-12-05 15:32:45]

I don't know what the file_select_helper does on the worker pool, so I can't
really verify that the constraints make sense

if you find a reviewer that can, or are sufficiently confident that these are
the right constraints, I'm happy to approve for owners

[fdoray, 2016-12-07 15:47:47]

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

[fdoray, 2016-12-07 15:47:47]

jsbell@: Please review this CL. In particular, make sure that the traits
mentioned in the CL description make sense for this task. Thanks!

Note: WorkerPool is being deprecated in favor of TaskScheduler. Read the design
doc
https://docs.google.com/document/d/1S2AAeoo1xa_vsLbDYBsDHCqhrkfiMgoIPlyRi6kxa...

Note: On shutdown, WorkerPool does not wait for tasks to run. To get the same
behavior in TaskScheduler, we used TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN.

[jsbell, 2016-12-12 22:36:19]

Unfortunately, I don't think I meet jochen@'s requirements for someone
"sufficiently confident" about the behavior here - I've only touched the file
once. brettw@ maybe?

From code inspection, the traits appear correct: DirectoryLister::Start()
immediately PostTasks DirectoryLister::Core::Start() to the passed runner, which
synchronously enumerates the directory, posting back to the origin runner when
complete. No specific priority, don't join on shutdown, does sync file I/O,
doesn't do any other blocking work.

So lgtm but that may not be enough.

[fdoray, 2016-12-21 19:19:48]

Description was changed from

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

With file IO:
  The task is allowed to perform synchronous IO operations.

No Wait (default):
  The task does not wait on things other than synchronous file IO
  operations (e.g. WaitableEvent, ConditionVariable, join a thread,
  join a process, blocking system call that doesn't involve
  interactions with the file system).

BUG=659191
==========

to

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

BUG=659191
==========

[fdoray, 2016-12-21 19:20:32]

On 2016/12/12 22:36:19, jsbell (OOO thru Jan 2) wrote:
> Unfortunately, I don't think I meet jochen@'s requirements for someone
> "sufficiently confident" about the behavior here - I've only touched the file
> once. brettw@ maybe?
> 
> From code inspection, the traits appear correct: DirectoryLister::Start()
> immediately PostTasks DirectoryLister::Core::Start() to the passed runner,
which
> synchronously enumerates the directory, posting back to the origin runner when
> complete. No specific priority, don't join on shutdown, does sync file I/O,
> doesn't do any other blocking work.
> 
> So lgtm but that may not be enough.

I'm sufficiently confident that these are the right constraints.

[fdoray, 2016-12-21 19:20:45]

Description was changed from

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

BUG=659191
==========

to

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

TBR=jochen@chromium.org
BUG=659191
==========

[fdoray, 2016-12-21 19:20:49]

The CQ bit was checked by fdoray@chromium.org

[fdoray, 2016-12-21 19:20:50]

The patchset sent to the CQ was uploaded after l-g-t-m from jsbell@chromium.org
Link to the patchset: https://codereview.chromium.org/2545723005/#ps40001
(title: "may block")

[commit-bot: I haz the power, 2016-12-21 19:21:30]

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, 2016-12-21 20:21:10]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1482348049880380,
"parent_rev": "069da668ed272a1f6c60ed47d3f4262faa040cb9", "commit_rev":
"43525866185fedbaa7afb31aeb4a2c86f6631797"}

[commit-bot: I haz the power, 2016-12-21 20:21:37]

Description was changed from

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

TBR=jochen@chromium.org
BUG=659191
==========

to

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

TBR=jochen@chromium.org
BUG=659191

Review-Url: https://codereview.chromium.org/2545723005
==========

[commit-bot: I haz the power, 2016-12-21 20:21:38]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-12-21 20:23:56]

Description was changed from

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

TBR=jochen@chromium.org
BUG=659191

Review-Url: https://codereview.chromium.org/2545723005
==========

to

==========
Use TaskScheduler instead of WorkerPool in file_select_helper.cc.

This CL replaces base::WorkerPool::PostTask() with
base::PostTaskWithTraits() call. The following traits are used:

Priority: Inherited (default)
  The priority is inherited from the calling context (i.e.
  TaskTraits takes the priority of the task that creates it).

Shutdown behavior: CONTINUE_ON_SHUTDOWN
  Tasks posted with this mode which have not started executing before
  shutdown is initiated will never run. Tasks with this mode running at
  shutdown will be ignored (the worker will not be joined).

May Block:
  Tasks with this trait 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.

No Sync Primitives (default):
  Tasks are not allowed to wait on waitable events/condition variables
  or to join threads/processes.

TBR=jochen@chromium.org
BUG=659191

Committed: https://crrev.com/9e2697603c48a60c78ca99ad404251d2764ec9c2
Cr-Commit-Position: refs/heads/master@{#440200}
==========

[commit-bot: I haz the power, 2016-12-21 20:23:56]

Patchset 3 (id:??) landed as
https://crrev.com/9e2697603c48a60c78ca99ad404251d2764ec9c2
Cr-Commit-Position: refs/heads/master@{#440200}