Implement a new child test helper for Android.

Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launched.

This implementation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests on Android.

BUG=585849
Committed: https://crrev.com/0027a09598062ce81944af809130692940bca515
Cr-Commit-Position: refs/heads/master@{#391130}

[Anand Mistry (off Chromium), 2016-04-26 07:13:05]

Description was changed from

==========
Re-write Android test child process launcher.

WIP!

BUG=585849
==========

to

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launcher.

This implemenation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests.

BUG=585849
==========

[Anand Mistry (off Chromium), 2016-04-26 07:13:25]

Description was changed from

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launcher.

This implemenation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests.

BUG=585849
==========

to

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launcher.

This implemenation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests.

BUG=585849
==========

[Anand Mistry (off Chromium), 2016-04-26 07:15:14]

amistry@chromium.org changed reviewers:
+ phajdan.jr@chromium.org, rockot@chromium.org

[Anand Mistry (off Chromium), 2016-04-26 07:15:15]

Please don't be mad... or sad...

[Ken Rockot(use gerrit already), 2016-04-26 16:10:57]

mojo lgtm - note there are also multiprocess (non-mojo) ipc tests in
//ipc/ipc_channel_unittest.cc disabled on Android for the same reason. Maybe
it's worth turning those on here as well.

[Paweł Hajdan Jr., 2016-04-26 20:19:42]

phajdan.jr@chromium.org changed reviewers:
+ mark@chromium.org

[Paweł Hajdan Jr., 2016-04-26 20:19:43]

+mark for multiprocess code

LGTM w/nits

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
File base/test/multiprocess_test.h (right):

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
base/test/multiprocess_test.h:77: // Wait for a test child to exit if the
alternate tech child implementation is
What's "alternate tech child"? Should "tech" change to "test"?

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
base/test/multiprocess_test.h:79: bool AndroidWaitForChildExitWithTimeout(
nit: WARN_UNUSED_RESULT

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
base/test/multiprocess_test.h:82: #endif
nit:  // defined(OS_ANDROID)

[Anand Mistry (off Chromium), 2016-04-26 23:50:39]

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
File base/test/multiprocess_test.h (right):

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
base/test/multiprocess_test.h:77: // Wait for a test child to exit if the
alternate tech child implementation is
On 2016/04/26 20:19:43, Paweł Hajdan Jr. wrote:
> What's "alternate tech child"? Should "tech" change to "test"?

Done.

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
base/test/multiprocess_test.h:79: bool AndroidWaitForChildExitWithTimeout(
On 2016/04/26 20:19:43, Paweł Hajdan Jr. wrote:
> nit: WARN_UNUSED_RESULT

Done.

https://codereview.chromium.org/1910233003/diff/120001/base/test/multiprocess...
base/test/multiprocess_test.h:82: #endif
On 2016/04/26 20:19:43, Paweł Hajdan Jr. wrote:
> nit:  // defined(OS_ANDROID)

Done.

[Anand Mistry (off Chromium), 2016-05-02 00:37:54]

mark: Ping! Unless there's someone else you think should be reviewing this
instead.

[Anand Mistry (off Chromium), 2016-05-02 00:38:56]

Description was changed from

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launcher.

This implemenation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests.

BUG=585849
==========

to

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launched.

This implementation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests on Android.

BUG=585849
==========

[Mark Mentovai, 2016-05-02 18:26:57]

LGTM in base. I was out of the office last week.

[Anand Mistry (off Chromium), 2016-05-02 23:30:58]

The CQ bit was checked by amistry@chromium.org

[Anand Mistry (off Chromium), 2016-05-02 23:30:58]

The patchset sent to the CQ was uploaded after l-g-t-m from rockot@chromium.org,
phajdan.jr@chromium.org
Link to the patchset: https://codereview.chromium.org/1910233003/#ps160001
(title: "Rebase.")

[commit-bot: I haz the power, 2016-05-02 23:31:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1910233003/160001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1910233003/160001

[commit-bot: I haz the power, 2016-05-03 00:53:02]

Description was changed from

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launched.

This implementation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests on Android.

BUG=585849
==========

to

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launched.

This implementation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests on Android.

BUG=585849
==========

[commit-bot: I haz the power, 2016-05-03 00:53:03]

Committed patchset #9 (id:160001)

[commit-bot: I haz the power, 2016-05-03 00:54:14]

Description was changed from

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launched.

This implementation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests on Android.

BUG=585849
==========

to

==========
Implement a new child test helper for Android.

On Android, there's no binary to exec(), therefore the existing spawning
mechanism fork()s the process at the current location. Because fork() only
forks the running thread, this causes problems if another thread (i.e. an
IO thread) is created before the child is launched.

This implementation works around this by forking a helper process very early,
and using that to create a new child.

Finally, use this to enable the Mojo multi-process tests on Android.

BUG=585849

Committed: https://crrev.com/0027a09598062ce81944af809130692940bca515
Cr-Commit-Position: refs/heads/master@{#391130}
==========

[commit-bot: I haz the power, 2016-05-03 00:54:15]

Patchset 9 (id:??) landed as
https://crrev.com/0027a09598062ce81944af809130692940bca515
Cr-Commit-Position: refs/heads/master@{#391130}