Revert of Get rid of UnsafeCurrent in Sampler

Revert of Get rid of UnsafeCurrent in Sampler (patchset #12 id:220001 of https://codereview.chromium.org/1858143003/ )

Reason for revert:
[Sheriff] Breaks tsan:
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20TSAN/builds/8999

Original issue's description:
> Get rid of UnsafeCurrent in Sampler
>
> Currently we are using UnsafeCurrent in async signal handler to acquire the
> isolate of VM thread, but we want to get rid of that since it prevents V8 from
> being thread agnostic.
>
> This patch replaces UnsafeCurrent with a static map, where we store a map of
> samplers for threads, and makes it accessible by signal handler.
>
> BUG=v8:4889
> LOG=n
>
> Committed: https://crrev.com/62fb4775fea0d56d8a175baf1d902213f6752168
> Cr-Commit-Position: refs/heads/master@{#35541}

TBR=jochen@chromium.org,alph@chromium.org,fmeawad@chromium.org,yangguo@chromium.org,lpy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4889
Committed: https://crrev.com/ba011836e4aea1116b6bf21907ece3704fd6cca0
Cr-Commit-Position: refs/heads/master@{#35545}

[Michael Achenbach, 2016-04-16 06:30:37]

Created Revert of Get rid of UnsafeCurrent in Sampler

[commit-bot: I haz the power, 2016-04-16 06:30:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1897673002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1897673002/1

[commit-bot: I haz the power, 2016-04-16 06:30:58]

Description was changed from

==========
Revert of Get rid of UnsafeCurrent in Sampler (patchset #12 id:220001 of
https://codereview.chromium.org/1858143003/ )

Reason for revert:
[Sheriff] Breaks tsan:
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20TSAN/builds/8999

Original issue's description:
> Get rid of UnsafeCurrent in Sampler
> 
> Currently we are using UnsafeCurrent in async signal handler to acquire the
> isolate of VM thread, but we want to get rid of that since it prevents V8 from
> being thread agnostic.
> 
> This patch replaces UnsafeCurrent with a static map, where we store a map of
> samplers for threads, and makes it accessible by signal handler.
> 
> BUG=v8:4889
> LOG=n
> 
> Committed: https://crrev.com/62fb4775fea0d56d8a175baf1d902213f6752168
> Cr-Commit-Position: refs/heads/master@{#35541}

TBR=jochen@chromium.org,alph@chromium.org,fmeawad@chromium.org,yangguo@chromi...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4889
==========

to

==========
Revert of Get rid of UnsafeCurrent in Sampler (patchset #12 id:220001 of
https://codereview.chromium.org/1858143003/ )

Reason for revert:
[Sheriff] Breaks tsan:
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20TSAN/builds/8999

Original issue's description:
> Get rid of UnsafeCurrent in Sampler
> 
> Currently we are using UnsafeCurrent in async signal handler to acquire the
> isolate of VM thread, but we want to get rid of that since it prevents V8 from
> being thread agnostic.
> 
> This patch replaces UnsafeCurrent with a static map, where we store a map of
> samplers for threads, and makes it accessible by signal handler.
> 
> BUG=v8:4889
> LOG=n
> 
> Committed: https://crrev.com/62fb4775fea0d56d8a175baf1d902213f6752168
> Cr-Commit-Position: refs/heads/master@{#35541}

TBR=jochen@chromium.org,alph@chromium.org,fmeawad@chromium.org,yangguo@chromi...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4889
==========

[commit-bot: I haz the power, 2016-04-16 06:30:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-16 06:33:09]

Description was changed from

==========
Revert of Get rid of UnsafeCurrent in Sampler (patchset #12 id:220001 of
https://codereview.chromium.org/1858143003/ )

Reason for revert:
[Sheriff] Breaks tsan:
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20TSAN/builds/8999

Original issue's description:
> Get rid of UnsafeCurrent in Sampler
> 
> Currently we are using UnsafeCurrent in async signal handler to acquire the
> isolate of VM thread, but we want to get rid of that since it prevents V8 from
> being thread agnostic.
> 
> This patch replaces UnsafeCurrent with a static map, where we store a map of
> samplers for threads, and makes it accessible by signal handler.
> 
> BUG=v8:4889
> LOG=n
> 
> Committed: https://crrev.com/62fb4775fea0d56d8a175baf1d902213f6752168
> Cr-Commit-Position: refs/heads/master@{#35541}

TBR=jochen@chromium.org,alph@chromium.org,fmeawad@chromium.org,yangguo@chromi...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4889
==========

to

==========
Revert of Get rid of UnsafeCurrent in Sampler (patchset #12 id:220001 of
https://codereview.chromium.org/1858143003/ )

Reason for revert:
[Sheriff] Breaks tsan:
https://build.chromium.org/p/client.v8/builders/V8%20Linux64%20TSAN/builds/8999

Original issue's description:
> Get rid of UnsafeCurrent in Sampler
>
> Currently we are using UnsafeCurrent in async signal handler to acquire the
> isolate of VM thread, but we want to get rid of that since it prevents V8 from
> being thread agnostic.
>
> This patch replaces UnsafeCurrent with a static map, where we store a map of
> samplers for threads, and makes it accessible by signal handler.
>
> BUG=v8:4889
> LOG=n
>
> Committed: https://crrev.com/62fb4775fea0d56d8a175baf1d902213f6752168
> Cr-Commit-Position: refs/heads/master@{#35541}

TBR=jochen@chromium.org,alph@chromium.org,fmeawad@chromium.org,yangguo@chromi...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4889

Committed: https://crrev.com/ba011836e4aea1116b6bf21907ece3704fd6cca0
Cr-Commit-Position: refs/heads/master@{#35545}
==========

[commit-bot: I haz the power, 2016-04-16 06:33:10]

Patchset 1 (id:??) landed as
https://crrev.com/ba011836e4aea1116b6bf21907ece3704fd6cca0
Cr-Commit-Position: refs/heads/master@{#35545}