[Mac] Work around potential pthread_mutex_destroy crashes

[Mac] Work around potential pthread_mutex_destroy crashes

This ports https://codereview.chromium.org/1323293005 to V8.
I'm not aware of any evidence that such crashes are currently
happening, but it's probably good to ship this workaround anyway.

BUG=chromium:517681
LOG=n

Committed: https://crrev.com/fd2dbf1d0124b8c1212226ccb668259b8eac7ff8
Cr-Commit-Position: refs/heads/master@{#36087}

[Jakob Kummerow, 2016-05-06 13:13:31]

jkummerow@chromium.org changed reviewers:
+ erikchen@chromium.org, jochen@chromium.org

[Jakob Kummerow, 2016-05-06 13:13:32]

Please take a look.

It appears V8 uses the terms "Mutex" and "LockGuard" for what Chromium calls
"Lock" and "AutoLock".

[erikchen, 2016-05-06 16:00:38]

lgtm

[jochen (gone - plz use gerrit), 2016-05-06 16:41:26]

lgtm

[Jakob Kummerow, 2016-05-06 16:53:16]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2016-05-06 16:53:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1959643002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1959643002/20001

[commit-bot: I haz the power, 2016-05-06 17:21:08]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-05-06 17:22:13]

Description was changed from

==========
[Mac] Work around potential pthread_mutex_destroy crashes

This ports https://codereview.chromium.org/1323293005 to V8.
I'm not aware of any evidence that such crashes are currently
happening, but it's probably good to ship this workaround anyway.

BUG=chromium:517681
LOG=n
==========

to

==========
[Mac] Work around potential pthread_mutex_destroy crashes

This ports https://codereview.chromium.org/1323293005 to V8.
I'm not aware of any evidence that such crashes are currently
happening, but it's probably good to ship this workaround anyway.

BUG=chromium:517681
LOG=n

Committed: https://crrev.com/fd2dbf1d0124b8c1212226ccb668259b8eac7ff8
Cr-Commit-Position: refs/heads/master@{#36087}
==========

[commit-bot: I haz the power, 2016-05-06 17:22:14]

Patchset 2 (id:??) landed as
https://crrev.com/fd2dbf1d0124b8c1212226ccb668259b8eac7ff8
Cr-Commit-Position: refs/heads/master@{#36087}