Share field trial allocator on MacOS

Share field trial allocator on MacOS

This CL shares the field trial allocator on MacOS. It depends on Mac having
POSIX shared memory support, but other than that it is basically the same as
the Linux CL: https://codereview.chromium.org/2530573002/. We just need to
edit some ifdefs.

BUG=663912

[lawrencewu, 2016-12-08 14:58:16]

Description was changed from

==========
add support for sharing field trials on mac

BUG=
==========

to

==========
Share field trial allocator on MacOS

This CL shares the field trial allocator on MacOS. It depends on Mac having
POSIX shared memory support, but other than that it is basically the same as
the Linux CL: https://codereview.chromium.org/2530573002/. We just need to
edit some ifdefs.

BUG=663912
==========

[Alexei Svitkine (slow), 2016-12-09 22:23:41]

asvitkine@chromium.org changed reviewers:
+ asvitkine@chromium.org

[Alexei Svitkine (slow), 2016-12-09 22:23:41]

lgtm assuming you tested and still works after all your refactors on the other
CL

https://codereview.chromium.org/2555453002/diff/1/base/memory/shared_memory_h...
File base/memory/shared_memory_handle_mac.cc (left):

https://codereview.chromium.org/2555453002/diff/1/base/memory/shared_memory_h...
base/memory/shared_memory_handle_mac.cc:180: 
Nit: Remove extra diff here.

[lawrencewu, 2016-12-09 22:31:14]

On 2016/12/09 22:23:41, Alexei Svitkine (slow) wrote:
> lgtm assuming you tested and still works after all your refactors on the other
> CL
> 
>
https://codereview.chromium.org/2555453002/diff/1/base/memory/shared_memory_h...
> File base/memory/shared_memory_handle_mac.cc (left):
> 
>
https://codereview.chromium.org/2555453002/diff/1/base/memory/shared_memory_h...
> base/memory/shared_memory_handle_mac.cc:180: 
> Nit: Remove extra diff here.

Closing: see https://codereview.chromium.org/2565683003/