Revert of Use TaskScheduler instead of WorkerPool in BackgroundTaskRunner.cpp

Revert of Use TaskScheduler instead of WorkerPool in BackgroundTaskRunner.cpp (patchset #1 id:1 of https://codereview.chromium.org/2685673005/ )

Reason for revert:
Reverting to see the effect on memory benchmarks.
BUG=691618
Original issue's description:
> Use TaskScheduler instead of WorkerPool in BackgroundTaskRunner.cpp
> 
> This CL replaces base::WorkerPool::PostTask() with
> base::PostTaskWithTraits(). The following traits are used:
> 
> Priority: Inherited (default)
>   The priority is inherited from the calling context (i.e. TaskTraits
>   are initialized with the priority of the current task).
> 
> 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).
> 
>   Note: Tasks that were previously posted to base::WorkerPool should
>   use this shutdown behavior because this is how base::WorkerPool
>   handles all its tasks.
> 
> *No* May Block (default):
>   Tasks may no block on synchronous file I/O operations or on sync
>   primitives.
> 
> BUG=659191
> 
> Review-Url: https://codereview.chromium.org/2685673005
> Cr-Commit-Position: refs/heads/master@{#449633}
> Committed: https://chromium.googlesource.com/chromium/src/+/99e56574537a8cf27af4c86f34e42fcad65e21c8

TBR=kinuko@chromium.org,haraken@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=659191
Review-Url: https://codereview.chromium.org/2812263003
Cr-Commit-Position: refs/heads/master@{#464121}
Committed: https://chromium.googlesource.com/chromium/src/+/24e5d1ddee9fa61587b6f0279a25792d0208b9f1

[fdoray, 2017-04-12 16:43:05]

The CQ bit was checked by fdoray@chromium.org

[fdoray, 2017-04-12 16:43:06]

Created Revert of Use TaskScheduler instead of WorkerPool in
BackgroundTaskRunner.cpp

[commit-bot: I haz the power, 2017-04-12 16:43:58]

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, 2017-04-12 16:48:15]

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

[commit-bot: I haz the power, 2017-04-12 16:48:16]

Try jobs failed on following builders:
  android_cronet on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_cron...)
  ios-device-xcode-clang on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device-xcode-...)
  ios-simulator on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/bui...)
  ios-simulator-xcode-clang on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator-xco...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)

[fdoray, 2017-04-12 17:21:28]

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

[commit-bot: I haz the power, 2017-04-12 17:22:34]

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

[fdoray, 2017-04-12 17:22:40]

The CQ bit was unchecked by fdoray@chromium.org

[fdoray, 2017-04-12 17:26:06]

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

[fdoray, 2017-04-12 17:26:24]

The CQ bit was unchecked by fdoray@chromium.org

[fdoray, 2017-04-12 17:27:57]

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

[commit-bot: I haz the power, 2017-04-12 17:28:28]

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

[fdoray, 2017-04-12 17:28:49]

The CQ bit was unchecked by fdoray@chromium.org

[fdoray, 2017-04-12 17:28:53]

The CQ bit was checked by fdoray@chromium.org

[commit-bot: I haz the power, 2017-04-12 17:29:07]

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, 2017-04-12 19:58:19]

CQ is committing da patch.

Bot data: {"patchset_id": 200001, "attempt_start_ts": 1492018133020440,
"parent_rev": "123caa27f5a800ea44c2e156a79464b1ebe92950", "commit_rev":
"24e5d1ddee9fa61587b6f0279a25792d0208b9f1"}

[commit-bot: I haz the power, 2017-04-12 19:59:10]

Description was changed from

==========
Revert of Use TaskScheduler instead of WorkerPool in BackgroundTaskRunner.cpp
(patchset #1 id:1 of https://codereview.chromium.org/2685673005/ )

Reason for revert:
Reverting to see the effect on memory benchmarks.
BUG=691618

Original issue's description:
> Use TaskScheduler instead of WorkerPool in BackgroundTaskRunner.cpp
> 
> This CL replaces base::WorkerPool::PostTask() with
> base::PostTaskWithTraits(). The following traits are used:
> 
> Priority: Inherited (default)
>   The priority is inherited from the calling context (i.e. TaskTraits
>   are initialized with the priority of the current task).
> 
> 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).
> 
>   Note: Tasks that were previously posted to base::WorkerPool should
>   use this shutdown behavior because this is how base::WorkerPool
>   handles all its tasks.
> 
> *No* May Block (default):
>   Tasks may no block on synchronous file I/O operations or on sync
>   primitives.
> 
> BUG=659191
> 
> Review-Url: https://codereview.chromium.org/2685673005
> Cr-Commit-Position: refs/heads/master@{#449633}
> Committed:
https://chromium.googlesource.com/chromium/src/+/99e56574537a8cf27af4c86f34e4...

TBR=kinuko@chromium.org,haraken@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=659191
==========

to

==========
Revert of Use TaskScheduler instead of WorkerPool in BackgroundTaskRunner.cpp
(patchset #1 id:1 of https://codereview.chromium.org/2685673005/ )

Reason for revert:
Reverting to see the effect on memory benchmarks.
BUG=691618

Original issue's description:
> Use TaskScheduler instead of WorkerPool in BackgroundTaskRunner.cpp
> 
> This CL replaces base::WorkerPool::PostTask() with
> base::PostTaskWithTraits(). The following traits are used:
> 
> Priority: Inherited (default)
>   The priority is inherited from the calling context (i.e. TaskTraits
>   are initialized with the priority of the current task).
> 
> 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).
> 
>   Note: Tasks that were previously posted to base::WorkerPool should
>   use this shutdown behavior because this is how base::WorkerPool
>   handles all its tasks.
> 
> *No* May Block (default):
>   Tasks may no block on synchronous file I/O operations or on sync
>   primitives.
> 
> BUG=659191
> 
> Review-Url: https://codereview.chromium.org/2685673005
> Cr-Commit-Position: refs/heads/master@{#449633}
> Committed:
https://chromium.googlesource.com/chromium/src/+/99e56574537a8cf27af4c86f34e4...

TBR=kinuko@chromium.org,haraken@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=659191

Review-Url: https://codereview.chromium.org/2812263003
Cr-Commit-Position: refs/heads/master@{#464121}
Committed:
https://chromium.googlesource.com/chromium/src/+/24e5d1ddee9fa61587b6f0279a25...
==========

[commit-bot: I haz the power, 2017-04-12 19:59:11]

Committed patchset #4 (id:200001) as
https://chromium.googlesource.com/chromium/src/+/24e5d1ddee9fa61587b6f0279a25...

[fdoray, 2017-05-30 14:26:26]

A revert of this CL (patchset #4 id:200001) has been created in
https://codereview.chromium.org/2914633002/ by fdoray@chromium.org.

The reason for reverting is: Relanding the patch set after the effect of
reverting it has been analyzed..