base: Make shared memory backed by Mach primitives by default.

base: Make shared memory backed by Mach primitives by default.

The type of shared memory used is controlled by an A/B experiment. If the
experiment isn't present, use Mach primitives.

BUG=466437
Committed: https://crrev.com/8b8e4212cef52b2cf924c27bb7c49e375306acb3
Cr-Commit-Position: refs/heads/master@{#361249}

[erikchen, 2015-11-21 02:02:56]

erikchen@chromium.org changed reviewers:
+ avi@chromium.org, mark@chromium.org

[erikchen, 2015-11-21 02:02:57]

mark: Please review base/
avi: Please review content/

[Avi (use Gerrit), 2015-11-21 14:14:44]

lgtm

[Mark Mentovai, 2015-11-21 14:55:47]

LGTM

https://codereview.chromium.org/1453383002/diff/20001/base/memory/shared_memo...
File base/memory/shared_memory_mac.cc (right):

https://codereview.chromium.org/1453383002/diff/20001/base/memory/shared_memo...
base/memory/shared_memory_mac.cc:56: group = SharedMemoryHandle::MACH;
NOTREACHED() too?

[erikchen, 2015-11-23 19:24:14]

https://codereview.chromium.org/1453383002/diff/20001/base/memory/shared_memo...
File base/memory/shared_memory_mac.cc (right):

https://codereview.chromium.org/1453383002/diff/20001/base/memory/shared_memo...
base/memory/shared_memory_mac.cc:56: group = SharedMemoryHandle::MACH;
On 2015/11/21 14:55:47, Mark Mentovai wrote:
> NOTREACHED() too?

No - for tests, this is always the block chosen.

[erikchen, 2015-11-23 19:24:17]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-11-23 19:26:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1453383002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1453383002/20001

[commit-bot: I haz the power, 2015-11-23 20:09:10]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-23 20:09:12]

Try jobs failed on following builders:
  mac_chromium_gn_rel on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_gn_r...)

[erikchen, 2015-11-23 22:12:56]

The CQ bit was checked by erikchen@chromium.org

[erikchen, 2015-11-23 22:12:56]

The patchset sent to the CQ was uploaded after l-g-t-m from mark@chromium.org,
avi@chromium.org
Link to the patchset: https://codereview.chromium.org/1453383002/#ps40001
(title: "Force a POSIX test to use POSIX shared memory.")

[commit-bot: I haz the power, 2015-11-23 22:15:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1453383002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1453383002/40001

[commit-bot: I haz the power, 2015-11-24 00:08:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-24 00:08:52]

Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[erikchen, 2015-11-24 00:37:16]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-11-24 00:43:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1453383002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1453383002/40001

[commit-bot: I haz the power, 2015-11-24 03:53:13]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-11-24 03:54:15]

Patchset 3 (id:??) landed as
https://crrev.com/8b8e4212cef52b2cf924c27bb7c49e375306acb3
Cr-Commit-Position: refs/heads/master@{#361249}

[Sami, 2015-11-25 12:12:57]

A revert of this CL (patchset #3 id:40001) has been created in
https://codereview.chromium.org/1472313002/ by skyostil@chromium.org.

The reason for reverting is: Speculative revert: 3 mac perf bots started timing
out in random tests around the time this patch landed. I'll keep an eye on the
waterfall and reland if things don't improve.

See https://code.google.com/p/chromium/issues/detail?id=561416 for logs..