Use ScopedTaskEnvironment instead of MessageLoop in media/capture/ unit tests

Use ScopedTaskEnvironment instead of MessageLoop in media/capture/ unit tests

ScopedTaskEnvironment allows usage of ThreadTaskRunnerHandle and
base/task_scheduler/post_task.h within its scope. It should be
instantiated in every unit test that uses either of these APIs
(i.e. no test should instantiate a MessageLoop directly).

Motivation for ScopedTaskEnvironment can be found in:
https://docs.google.com/document/d/1QabRo8c7D9LsYY3cEcaPQbOCLo8Tu-6VLykYXyl3Pkk/edit

BUG=708584
Review-Url: https://codereview.chromium.org/2859273004
Cr-Commit-Position: refs/heads/master@{#469691}
Committed: https://chromium.googlesource.com/chromium/src/+/5742c3808b947b73c4e279c2f753e59e284a1910

[Chandan, 2017-05-05 13:00:48]

The CQ bit was checked by c.padhi@samsung.com to run a CQ dry run

[commit-bot: I haz the power, 2017-05-05 13:01:04]

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, 2017-05-05 14:27:13]

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

[commit-bot: I haz the power, 2017-05-05 14:27:14]

Dry run: This issue passed the CQ dry run.

[Chandan, 2017-05-05 14:36:48]

c.padhi@samsung.com changed reviewers:
+ chfremer@chromium.org, fdoray@chromium.org

[Chandan, 2017-05-05 14:36:49]

PTAL. Thank you.

[chfremer, 2017-05-05 16:34:39]

lgtm

[Chandan, 2017-05-05 17:02:16]

The CQ bit was checked by c.padhi@samsung.com

[commit-bot: I haz the power, 2017-05-05 17:03:10]

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, 2017-05-05 17:09:57]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1494003736703060, "parent_rev":
"97b20197a53d323f7b2d92581d97817ea85ea0a4", "commit_rev":
"5742c3808b947b73c4e279c2f753e59e284a1910"}

[commit-bot: I haz the power, 2017-05-05 17:11:13]

Description was changed from

==========
Use ScopedTaskEnvironment instead of MessageLoop in media/capture/ unit tests

ScopedTaskEnvironment allows usage of ThreadTaskRunnerHandle and
base/task_scheduler/post_task.h within its scope. It should be
instantiated in every unit test that uses either of these APIs
(i.e. no test should instantiate a MessageLoop directly).

Motivation for ScopedTaskEnvironment can be found in:
https://docs.google.com/document/d/1QabRo8c7D9LsYY3cEcaPQbOCLo8Tu-6VLykYXyl3P...

BUG=708584
==========

to

==========
Use ScopedTaskEnvironment instead of MessageLoop in media/capture/ unit tests

ScopedTaskEnvironment allows usage of ThreadTaskRunnerHandle and
base/task_scheduler/post_task.h within its scope. It should be
instantiated in every unit test that uses either of these APIs
(i.e. no test should instantiate a MessageLoop directly).

Motivation for ScopedTaskEnvironment can be found in:
https://docs.google.com/document/d/1QabRo8c7D9LsYY3cEcaPQbOCLo8Tu-6VLykYXyl3P...

BUG=708584

Review-Url: https://codereview.chromium.org/2859273004
Cr-Commit-Position: refs/heads/master@{#469691}
Committed:
https://chromium.googlesource.com/chromium/src/+/5742c3808b947b73c4e279c2f753...
==========

[commit-bot: I haz the power, 2017-05-05 17:11:15]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/5742c3808b947b73c4e279c2f753...