Revert of [heap] Don't unmap new space pages while sweeping is active

Revert of [heap] Don't unmap new space pages while sweeping is active (patchset #4 id:80001 of https://codereview.chromium.org/2250423002/ )

Reason for revert:
The barrier in newspace is still needed.

Original issue's description:
> [heap] Don't unmap new space pages while sweeping is active
>
> - The barrier for scavenge only checked for whether new space pages were swept.
>   This is not enough as a concurrent task could still hang right before trying to
>   lock the page for sweeping. Remove the barrier completely.
> - Avoid unmapping of new space pages while sweeping using a delayed list that
>   gets emptied upon the next call to the unmapper.
>
> BUG=chromium:628984
> R=hpayer@chromium.org
>
> Committed: https://crrev.com/982b399423e6bd941cabb2b825031cd8d5eb4980
> Cr-Commit-Position: refs/heads/master@{#38710}

TBR=hpayer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:628984
Committed: https://crrev.com/4a1f2807d6da046367afd243159e40275ad9f8c6
Cr-Commit-Position: refs/heads/master@{#38712}

[Michael Lippautz, 2016-08-18 11:29:46]

The CQ bit was checked by mlippautz@chromium.org

[Michael Lippautz, 2016-08-18 11:29:47]

Created Revert of [heap] Don't unmap new space pages while sweeping is active

[commit-bot: I haz the power, 2016-08-18 11:29:49]

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, 2016-08-18 11:30:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-18 11:30:21]

Description was changed from

==========
Revert of [heap] Don't unmap new space pages while sweeping is active (patchset
#4 id:80001 of https://codereview.chromium.org/2250423002/ )

Reason for revert:
The barrier in newspace is still needed.

Original issue's description:
> [heap] Don't unmap new space pages while sweeping is active
> 
> - The barrier for scavenge only checked for whether new space pages were
swept.
>   This is not enough as a concurrent task could still hang right before trying
to
>   lock the page for sweeping. Remove the barrier completely.
> - Avoid unmapping of new space pages while sweeping using a delayed list that
>   gets emptied upon the next call to the unmapper.
> 
> BUG=chromium:628984
> R=hpayer@chromium.org
> 
> Committed: https://crrev.com/982b399423e6bd941cabb2b825031cd8d5eb4980
> Cr-Commit-Position: refs/heads/master@{#38710}

TBR=hpayer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:628984
==========

to

==========
Revert of [heap] Don't unmap new space pages while sweeping is active (patchset
#4 id:80001 of https://codereview.chromium.org/2250423002/ )

Reason for revert:
The barrier in newspace is still needed.

Original issue's description:
> [heap] Don't unmap new space pages while sweeping is active
>
> - The barrier for scavenge only checked for whether new space pages were
swept.
>   This is not enough as a concurrent task could still hang right before trying
to
>   lock the page for sweeping. Remove the barrier completely.
> - Avoid unmapping of new space pages while sweeping using a delayed list that
>   gets emptied upon the next call to the unmapper.
>
> BUG=chromium:628984
> R=hpayer@chromium.org
>
> Committed: https://crrev.com/982b399423e6bd941cabb2b825031cd8d5eb4980
> Cr-Commit-Position: refs/heads/master@{#38710}

TBR=hpayer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:628984

Committed: https://crrev.com/4a1f2807d6da046367afd243159e40275ad9f8c6
Cr-Commit-Position: refs/heads/master@{#38712}
==========

[commit-bot: I haz the power, 2016-08-18 11:30:23]

Patchset 1 (id:??) landed as
https://crrev.com/4a1f2807d6da046367afd243159e40275ad9f8c6
Cr-Commit-Position: refs/heads/master@{#38712}