Corrections:
- 'N' is documented here: https://msdn.microsoft.com/en-us/library/yeby3zcb.aspx.
- this is probably the default on Windows for consistency with *nix.
- 'e' is the character to disable sharing for glibc (https://www.gnu.org/software/libc/manual/html_node/Opening-Streams.html).

Adding Mac and Linux to the affected platforms. This "share-by-default" policy has caused problems on Windows (see  issue 671990 ). Is there any reason not to change base::OpenFile so that this is disabled by default? We could define our own mode character to enable sharing where needed.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d0bc44fa24fba9f483aaddae8e2c29df3524a5d6

commit d0bc44fa24fba9f483aaddae8e2c29df3524a5d6
Author: grt <grt@chromium.org>
Date: Mon Feb 13 17:52:17 2017

Stop base::OpenFile from leaking fds/handles into child procs.

BUG= 688362 
TEST=New FileUtilTest.OpenFileNoInheritance fails with previous impl, passes with new impl.

Review-Url: https://codereview.chromium.org/2687713003
Cr-Commit-Position: refs/heads/master@{#449999}

[modify] https://crrev.com/d0bc44fa24fba9f483aaddae8e2c29df3524a5d6/base/files/file_util.h
[modify] https://crrev.com/d0bc44fa24fba9f483aaddae8e2c29df3524a5d6/base/files/file_util_posix.cc
[modify] https://crrev.com/d0bc44fa24fba9f483aaddae8e2c29df3524a5d6/base/files/file_util_unittest.cc
[modify] https://crrev.com/d0bc44fa24fba9f483aaddae8e2c29df3524a5d6/base/files/file_util_win.cc
[modify] https://crrev.com/d0bc44fa24fba9f483aaddae8e2c29df3524a5d6/build/sanitizers/lsan_suppressions.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/mini_chromium/+/3a2d52d74c9af5277bf6456cc00ae728f89c4898

commit 3a2d52d74c9af5277bf6456cc00ae728f89c4898
Author: Mark Mentovai <mark@chromium.org>
Date: Tue Feb 28 21:13:52 2017

Use O_CLOEXEC (and O_NOCTTY) when calling open()

Equivalent to https://codereview.chromium.org/2725713002/.

BUG= chromium:688362 

Change-Id: I02b706af113c2ad8b0436464c2cc5abd2b5bc62e
Reviewed-on: https://chromium-review.googlesource.com/447998
Reviewed-by: Scott Graham <scottmg@chromium.org>

[modify] https://crrev.com/3a2d52d74c9af5277bf6456cc00ae728f89c4898/base/rand_util.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/crashpad/crashpad.git/+/58aac1bd87ce40f0f67af1a504c278509412555b

commit 58aac1bd87ce40f0f67af1a504c278509412555b
Author: Mark Mentovai <mark@chromium.org>
Date: Tue Feb 28 21:16:41 2017

Set FD_CLOEXEC on file descriptors obtained from open() and fopen()

Includes an update of mini_chromium to 3a2d52d74c9a:

3a2d52d74c9a Use O_CLOEXEC (and O_NOCTTY) when calling open()

BUG= chromium:688362 

Change-Id: I2bdf86efe4e6559ecb77492ac5bdc728aa035889
Reviewed-on: https://chromium-review.googlesource.com/447999
Reviewed-by: Scott Graham <scottmg@chromium.org>

[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/DEPS
[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/client/crash_report_database_mac.mm
[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/tools/mac/catch_exception_tool.cc
[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/util/file/file_io_posix.cc
[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/util/mac/xattr_test.cc
[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/util/posix/close_multiple.cc
[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/util/posix/close_stdio.cc
[modify] https://crrev.com/58aac1bd87ce40f0f67af1a504c278509412555b/util/posix/process_info_test.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4cec49482d07386181836bfd950a06445421471d

commit 4cec49482d07386181836bfd950a06445421471d
Author: mark <mark@chromium.org>
Date: Tue Feb 28 23:56:00 2017

Use O_CLOEXEC when calling open() in rand_util_posix

BUG= 688362 

Review-Url: https://codereview.chromium.org/2725713002
Cr-Commit-Position: refs/heads/master@{#453754}

[modify] https://crrev.com/4cec49482d07386181836bfd950a06445421471d/base/rand_util_posix.cc