Fix Android multi-process tests on M.

Fix Android multi-process tests on M.

On M, there are two issues:
1. Fd 4 is important, although I don't know what it is.
2. Some test environment setup can't be done in the child process.

BUG=608732, 585849
Committed: https://crrev.com/931b0d62745156f2d7cf8ba43eb4de6a238c5a24
Cr-Commit-Position: refs/heads/master@{#391692}

[Anand Mistry (off Chromium), 2016-05-04 04:52:06]

Description was changed from

==========
Fix Android multi-process tests on M.

On M, there are two issues:
1. Fd 4 is important, although I don't know what it is.
2. Some test environment setup can't be done in the child process.

BUG=608732
==========

to

==========
Fix Android multi-process tests on M.

On M, there are two issues:
1. Fd 4 is important, although I don't know what it is.
2. Some test environment setup can't be done in the child process.

BUG=608732,585849
==========

[Anand Mistry (off Chromium), 2016-05-04 04:53:43]

amistry@chromium.org changed reviewers:
+ mark@chromium.org

[Anand Mistry (off Chromium), 2016-05-04 04:53:44]

Sigh!

[Mark Mentovai, 2016-05-04 12:07:12]

LGTM otherwise

https://codereview.chromium.org/1952513003/diff/1/base/posix/global_descripto...
File base/posix/global_descriptors.h (right):

https://codereview.chromium.org/1952513003/diff/1/base/posix/global_descripto...
base/posix/global_descriptors.h:59: // 4 used by... something important on
Android M.
Wish we had more confidence in what this was. What if it’s a leaked FD to
something that we really don’t want access to?

[Anand Mistry (off Chromium), 2016-05-04 21:48:43]

https://codereview.chromium.org/1952513003/diff/1/base/posix/global_descripto...
File base/posix/global_descriptors.h (right):

https://codereview.chromium.org/1952513003/diff/1/base/posix/global_descripto...
base/posix/global_descriptors.h:59: // 4 used by... something important on
Android M.
On 2016/05/04 12:07:12, Mark Mentovai wrote:
> Wish we had more confidence in what this was. What if it’s a leaked FD to
> something that we really don’t want access to?

The problem I came across is that closing or dup'ing over this fd will hang.
Even in the forked helper process which has no need to access anything beside
the stdout/stderr and the parent pipe. All I know is that this is a socket or
pipe (it's not a file). I didn't do any further digging as to what this is.

Fortunately, I don't believe this is used outside of tests. The normal Android
child process starter (in content/) doesn't have any control over fd mappings
due to all the Java that runs along side the C++ in the same process. So the
test child helper should be the only thing on Android which uses this.

[Anand Mistry (off Chromium), 2016-05-04 23:35:45]

The CQ bit was checked by amistry@chromium.org

[commit-bot: I haz the power, 2016-05-04 23:36:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1952513003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1952513003/1

[commit-bot: I haz the power, 2016-05-04 23:41:02]

Description was changed from

==========
Fix Android multi-process tests on M.

On M, there are two issues:
1. Fd 4 is important, although I don't know what it is.
2. Some test environment setup can't be done in the child process.

BUG=608732,585849
==========

to

==========
Fix Android multi-process tests on M.

On M, there are two issues:
1. Fd 4 is important, although I don't know what it is.
2. Some test environment setup can't be done in the child process.

BUG=608732,585849
==========

[commit-bot: I haz the power, 2016-05-04 23:41:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-04 23:42:48]

Description was changed from

==========
Fix Android multi-process tests on M.

On M, there are two issues:
1. Fd 4 is important, although I don't know what it is.
2. Some test environment setup can't be done in the child process.

BUG=608732,585849
==========

to

==========
Fix Android multi-process tests on M.

On M, there are two issues:
1. Fd 4 is important, although I don't know what it is.
2. Some test environment setup can't be done in the child process.

BUG=608732,585849

Committed: https://crrev.com/931b0d62745156f2d7cf8ba43eb4de6a238c5a24
Cr-Commit-Position: refs/heads/master@{#391692}
==========

[commit-bot: I haz the power, 2016-05-04 23:42:49]

Patchset 1 (id:??) landed as
https://crrev.com/931b0d62745156f2d7cf8ba43eb4de6a238c5a24
Cr-Commit-Position: refs/heads/master@{#391692}