Revert of Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

Revert of Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h (patchset #6 id:470001 of https://codereview.chromium.org/2690533002/ )

Reason for revert:
This patch is causing failures on the CrOS build bot:

../../chrome/browser/chromeos/login/wizard_controller.cc:225:42: error: member access into incomplete type 'base::SequencedWorkerPool'
  DCHECK(BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
                                         ^
../../base/threading/thread_restrictions.h:93:7: note: forward declaration of 'base::SequencedWorkerPool'
class SequencedWorkerPool;
      ^
1 error generated.

Original issue's description:
> Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h
> 
> This CL removes #include to sequenced_worker_pool.h in sequence_checker.h
> by hiding its members into a nested class, and adds #include and forward
> decls to other files as needed.
> 
> Note that the non trivial diffs are in sequence_checker_impl.{h,cc} only.
> 
> The header dependency from sequence_checker.h to sequenced_worker_pool.h
> prevents other headers to use sequence_checker.h due to a dependency
> cycle.
> 
> TBR=sky@chromium.org, kinuko@chromium.org, rdsmith@chromium.org, qinmin@chromium.org, marq@chromium.org, rockot@chromium.org, blundell@chromium.org, oshima@chromium.org, slan@chromium.org, boliu@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2690533002
> Cr-Original-Commit-Position: refs/heads/master@{#450321}
> Committed: https://chromium.googlesource.com/chromium/src/+/d502a3f2fa0b673a5082c1d601298bd114a9d237
> Review-Url: https://codereview.chromium.org/2690533002
> Cr-Commit-Position: refs/heads/master@{#450384}
> Committed: https://chromium.googlesource.com/chromium/src/+/70b7c5d796420107930c72d4ad82e0c850166b1a

TBR=gab@chromium.org,sky@chromium.org,kinuko@chromium.org,rdsmith@chromium.org,qinmin@chromium.org,marq@chromium.org,rockot@chromium.org,blundell@chromium.org,oshima@chromium.org,slan@chromium.org,boliu@chromium.org,msramek@chromium.org,tzik@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.chromium.org/2694813005
Cr-Commit-Position: refs/heads/master@{#450402}
Committed: https://chromium.googlesource.com/chromium/src/+/72c70c9d1f6b5453aeb518610b2fa581bed511aa

[Garrett Casto, 2017-02-14 18:01:17]

The CQ bit was checked by gcasto@chromium.org

[Garrett Casto, 2017-02-14 18:01:21]

Created Revert of Remove header dependencies from sequence_checker.h to
sequenced_worker_pool.h

[Garrett Casto, 2017-02-14 18:02:19]

On 2017/02/14 18:01:21, Garrett Casto wrote:
> Created Revert of Remove header dependencies from sequence_checker.h to
> sequenced_worker_pool.h

Forgot to put a link to the bot in the description.
https://build.chromium.org/p/chromium.chrome/builders/Google%20Chrome%20Chrom...

[commit-bot: I haz the power, 2017-02-14 18:02:24]

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, 2017-02-14 18:06:06]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1487095277732660, "parent_rev":
"86cf3df9dfe584e7663daa42017ca7629459e740", "commit_rev":
"72c70c9d1f6b5453aeb518610b2fa581bed511aa"}

[commit-bot: I haz the power, 2017-02-14 18:06:49]

Description was changed from

==========
Revert of Remove header dependencies from sequence_checker.h to
sequenced_worker_pool.h (patchset #6 id:470001 of
https://codereview.chromium.org/2690533002/ )

Reason for revert:
This patch is causing failures on the CrOS build bot:

../../chrome/browser/chromeos/login/wizard_controller.cc:225:42: error: member
access into incomplete type 'base::SequencedWorkerPool'
  DCHECK(BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
                                         ^
../../base/threading/thread_restrictions.h:93:7: note: forward declaration of
'base::SequencedWorkerPool'
class SequencedWorkerPool;
      ^
1 error generated.

Original issue's description:
> Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h
> 
> This CL removes #include to sequenced_worker_pool.h in sequence_checker.h
> by hiding its members into a nested class, and adds #include and forward
> decls to other files as needed.
> 
> Note that the non trivial diffs are in sequence_checker_impl.{h,cc} only.
> 
> The header dependency from sequence_checker.h to sequenced_worker_pool.h
> prevents other headers to use sequence_checker.h due to a dependency
> cycle.
> 
> TBR=sky@chromium.org, kinuko@chromium.org, rdsmith@chromium.org,
qinmin@chromium.org, marq@chromium.org, rockot@chromium.org,
blundell@chromium.org, oshima@chromium.org, slan@chromium.org,
boliu@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2690533002
> Cr-Original-Commit-Position: refs/heads/master@{#450321}
> Committed:
https://chromium.googlesource.com/chromium/src/+/d502a3f2fa0b673a5082c1d60129...
> Review-Url: https://codereview.chromium.org/2690533002
> Cr-Commit-Position: refs/heads/master@{#450384}
> Committed:
https://chromium.googlesource.com/chromium/src/+/70b7c5d796420107930c72d4ad82...

TBR=gab@chromium.org,sky@chromium.org,kinuko@chromium.org,rdsmith@chromium.or...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
==========

to

==========
Revert of Remove header dependencies from sequence_checker.h to
sequenced_worker_pool.h (patchset #6 id:470001 of
https://codereview.chromium.org/2690533002/ )

Reason for revert:
This patch is causing failures on the CrOS build bot:

../../chrome/browser/chromeos/login/wizard_controller.cc:225:42: error: member
access into incomplete type 'base::SequencedWorkerPool'
  DCHECK(BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
                                         ^
../../base/threading/thread_restrictions.h:93:7: note: forward declaration of
'base::SequencedWorkerPool'
class SequencedWorkerPool;
      ^
1 error generated.

Original issue's description:
> Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h
> 
> This CL removes #include to sequenced_worker_pool.h in sequence_checker.h
> by hiding its members into a nested class, and adds #include and forward
> decls to other files as needed.
> 
> Note that the non trivial diffs are in sequence_checker_impl.{h,cc} only.
> 
> The header dependency from sequence_checker.h to sequenced_worker_pool.h
> prevents other headers to use sequence_checker.h due to a dependency
> cycle.
> 
> TBR=sky@chromium.org, kinuko@chromium.org, rdsmith@chromium.org,
qinmin@chromium.org, marq@chromium.org, rockot@chromium.org,
blundell@chromium.org, oshima@chromium.org, slan@chromium.org,
boliu@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2690533002
> Cr-Original-Commit-Position: refs/heads/master@{#450321}
> Committed:
https://chromium.googlesource.com/chromium/src/+/d502a3f2fa0b673a5082c1d60129...
> Review-Url: https://codereview.chromium.org/2690533002
> Cr-Commit-Position: refs/heads/master@{#450384}
> Committed:
https://chromium.googlesource.com/chromium/src/+/70b7c5d796420107930c72d4ad82...

TBR=gab@chromium.org,sky@chromium.org,kinuko@chromium.org,rdsmith@chromium.or...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.chromium.org/2694813005
Cr-Commit-Position: refs/heads/master@{#450402}
Committed:
https://chromium.googlesource.com/chromium/src/+/72c70c9d1f6b5453aeb518610b2f...
==========

[commit-bot: I haz the power, 2017-02-14 18:06:50]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/72c70c9d1f6b5453aeb518610b2f...

[Garrett Casto, 2017-02-14 18:10:18]

On 2017/02/14 18:06:50, commit-bot: I haz the power wrote:
> Committed patchset #1 (id:1) as
>
https://chromium.googlesource.com/chromium/src/+/72c70c9d1f6b5453aeb518610b2f...

Looks like this also caused a failure in the Windows builder
(https://build.chromium.org/p/chromium.chrome/builders/Google%20Chrome%20Win/b...):

ninja -t msvc -e environment.x86 -- C:\b\c\cipd\goma/gomacc.exe
"C:\b\depot_tools\win_toolchain\vs_files\d3cb0e37bdd120ad0ac4650b674b09e81be45616\VC\bin\amd64_x86/cl.exe"
/nologo /showIncludes /FC
@obj/chrome/browser/ui/ui_1/version_updater_win.obj.rsp /c
../../chrome/browser/ui/webui/help/version_updater_win.cc
/Foobj/chrome/browser/ui/ui_1/version_updater_win.obj
/Fd"obj/chrome/browser/ui/ui_1_cc.pdb"
c:\b\c\b\win_chrome\src\chrome\browser\ui\webui\help\version_updater_win.cc(58):
error C2664: 'bool base::PostTaskAndReplyWithResult<R,bool>(base::TaskRunner
*,const tracked_objects::Location &,base::Callback<R
(void),base::internal::CopyMode::Copyable,base::internal::RepeatMode::Repeating>,base::Callback<void
(bool),base::internal::CopyMode::Copyable,base::internal::RepeatMode::Repeating>)':
cannot convert argument 1 from 'base::SequencedWorkerPool *' to
'base::TaskRunner *'
        with
        [
            R=bool
        ]
c:\b\c\b\win_chrome\src\chrome\browser\ui\webui\help\version_updater_win.cc(58):
note: Types pointed to are unrelated; conversion requires reinterpret_cast,
C-style cast or function-style cast
[31889/38409] CXX obj/chrome/browser/ui/ui_2/about_handler.obj