Revert of Add thread checking to RunLoop, deprecate MessageLoopRunner.

Revert of Add thread checking to RunLoop, deprecate MessageLoopRunner. (patchset #4 id:20002 of https://codereview.chromium.org/2537893002/ )

Reason for revert:
Speculative revert in an effort to pinpoint the cause of http://crbug.com/670844 - will reland if the flake doesn't clear

Original issue's description:
> Add thread checker to base::RunLoop.
>
> The purpose is to make sure that after switching users of
> MessageLoopRunner to RunLoop we won't lose any correctness checks.
>
> Also add a comment that encourages to use RunLoop where possible, and
> rename GetQuitTaskForRunLoop to GetDeferredQuitTaskForRunLoop to convey
> is purpose clearly.
>
> BUG=668707
>
> Committed: https://crrev.com/dd10720676efff002490f702118e052dcd210f18
> Cr-Commit-Position: refs/heads/master@{#435924}

TBR=avi@chromium.org,thakis@chromium.org,asargent@chromium.org,ahest@yandex-team.ru
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=668707
Committed: https://crrev.com/f8675b380dff12f69ad3b61920f9e8fdcfcadae8
Cr-Commit-Position: refs/heads/master@{#436035}

[Ken Rockot(use gerrit already), 2016-12-02 21:30:49]

The CQ bit was checked by rockot@chromium.org

[Ken Rockot(use gerrit already), 2016-12-02 21:30:49]

Created Revert of Add thread checking to RunLoop, deprecate MessageLoopRunner.

[commit-bot: I haz the power, 2016-12-02 21:31:28]

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 21:33:35]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1480714249046820, "parent_rev":
"52c5494be0eff4d28037dd791498ddc7a081b82f", "commit_rev":
"687342df9cdaeb996b327de064091149954edbd7"}

[commit-bot: I haz the power, 2016-12-02 21:34:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-02 21:38:02]

Description was changed from

==========
Revert of Add thread checking to RunLoop, deprecate MessageLoopRunner. (patchset
#4 id:20002 of https://codereview.chromium.org/2537893002/ )

Reason for revert:
Speculative revert in an effort to pinpoint the cause of http://crbug.com/670844
- will reland if the flake doesn't clear

Original issue's description:
> Add thread checker to base::RunLoop.
> 
> The purpose is to make sure that after switching users of
> MessageLoopRunner to RunLoop we won't lose any correctness checks.
> 
> Also add a comment that encourages to use RunLoop where possible, and
> rename GetQuitTaskForRunLoop to GetDeferredQuitTaskForRunLoop to convey
> is purpose clearly.
> 
> BUG=668707
> 
> Committed: https://crrev.com/dd10720676efff002490f702118e052dcd210f18
> Cr-Commit-Position: refs/heads/master@{#435924}

TBR=avi@chromium.org,thakis@chromium.org,asargent@chromium.org,ahest@yandex-t...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=668707
==========

to

==========
Revert of Add thread checking to RunLoop, deprecate MessageLoopRunner. (patchset
#4 id:20002 of https://codereview.chromium.org/2537893002/ )

Reason for revert:
Speculative revert in an effort to pinpoint the cause of http://crbug.com/670844
- will reland if the flake doesn't clear

Original issue's description:
> Add thread checker to base::RunLoop.
>
> The purpose is to make sure that after switching users of
> MessageLoopRunner to RunLoop we won't lose any correctness checks.
>
> Also add a comment that encourages to use RunLoop where possible, and
> rename GetQuitTaskForRunLoop to GetDeferredQuitTaskForRunLoop to convey
> is purpose clearly.
>
> BUG=668707
>
> Committed: https://crrev.com/dd10720676efff002490f702118e052dcd210f18
> Cr-Commit-Position: refs/heads/master@{#435924}

TBR=avi@chromium.org,thakis@chromium.org,asargent@chromium.org,ahest@yandex-t...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=668707

Committed: https://crrev.com/f8675b380dff12f69ad3b61920f9e8fdcfcadae8
Cr-Commit-Position: refs/heads/master@{#436035}
==========

[commit-bot: I haz the power, 2016-12-02 21:38:03]

Patchset 1 (id:??) landed as
https://crrev.com/f8675b380dff12f69ad3b61920f9e8fdcfcadae8
Cr-Commit-Position: refs/heads/master@{#436035}