Use ScopedTaskEnvironment instead of MessageLoop in components unit tests.

Use ScopedTaskEnvironment instead of MessageLoop in components 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
R=gab@chromium.org
TBR=sdefresne@chromium.org

Review-Url: https://codereview.chromium.org/2798963003
Cr-Commit-Position: refs/heads/master@{#462510}
Committed: https://chromium.googlesource.com/chromium/src/+/0d83127c40b39d0e9a54c1c1a474632017b9fc34

[fdoray, 2017-04-05 19:42:40]

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

[fdoray, 2017-04-05 19:42:42]

gab@: PTAL

The change will then be TBRed to the owner.

[commit-bot: I haz the power, 2017-04-05 19:43:07]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[gab, 2017-04-05 20:54:30]

lgtm

[commit-bot: I haz the power, 2017-04-05 22:25:46]

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

[commit-bot: I haz the power, 2017-04-05 22:25:47]

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

[sdefresne, 2017-04-06 09:24:56]

lgtm

[fdoray, 2017-04-06 15:27:36]

The CQ bit was checked by fdoray@chromium.org

[commit-bot: I haz the power, 2017-04-06 15:28:19]

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, 2017-04-06 16:50:24]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1491492456419190, "parent_rev":
"4cf067df249b8dbf265eeb944ed7c9b0ef420b08", "commit_rev":
"0d83127c40b39d0e9a54c1c1a474632017b9fc34"}

[commit-bot: I haz the power, 2017-04-06 16:51:19]

Description was changed from

==========
Use ScopedTaskEnvironment instead of MessageLoop in components 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
R=gab@chromium.org
TBR=sdefresne@chromium.org
==========

to

==========
Use ScopedTaskEnvironment instead of MessageLoop in components 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
R=gab@chromium.org
TBR=sdefresne@chromium.org

Review-Url: https://codereview.chromium.org/2798963003
Cr-Commit-Position: refs/heads/master@{#462510}
Committed:
https://chromium.googlesource.com/chromium/src/+/0d83127c40b39d0e9a54c1c1a474...
==========

[commit-bot: I haz the power, 2017-04-06 16:51:20]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/0d83127c40b39d0e9a54c1c1a474...