Test service as minimum repro for sharing memory handle

NOT INTENDED FOR LANDING

Adds a test service for reproducing an issue with sending a shared memory handle
from a Mojo service to a client. The test fails on OSX but passes on other 
platforms.

TEST=service_unittests --gtest_filter="TestServiceTest.ReceiveTestBufferHandle"

[chfremer, 2017-04-20 22:48:37]

Description was changed from

==========
NOT INTENDED FOR LANDING

Adds a test service for reproducing an issue with sending a shared memory handle
from a Mojo service to a client.
==========

to

==========
NOT INTENDED FOR LANDING

Adds a test service for reproducing an issue with sending a shared memory handle
from a Mojo service to a client.
==========

[chfremer, 2017-04-20 23:00:33]

Patchset #1 (id:1) has been deleted

[chfremer, 2017-04-20 23:19:09]

Description was changed from

==========
NOT INTENDED FOR LANDING

Adds a test service for reproducing an issue with sending a shared memory handle
from a Mojo service to a client.
==========

to

==========
NOT INTENDED FOR LANDING

Adds a test service for reproducing an issue with sending a shared memory handle
from a Mojo service to a client. The test fails on OSX but passes on other 
platforms.

TEST=service_unittests --gtest_filter="TestServiceTest.ReceiveTestBufferHandle"
==========

[Ken Rockot(use gerrit already), 2017-04-25 07:37:11]

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

[Ken Rockot(use gerrit already), 2017-04-25 07:37:11]

BTW https://chromium-review.googlesource.com/486133 fixes this for reals

[Ken Rockot(use gerrit already), 2017-04-25 21:00:21]

The CQ bit was checked by rockot@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-04-25 21:01:06]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-25 21:09:10]

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

[commit-bot: I haz the power, 2017-04-25 21:09:11]

Dry run: Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)