Reset TaskScheduler during PepperToVideoTrackAdapterTest tear down.

Reset TaskScheduler during PepperToVideoTrackAdapterTest tear down.

PepperToVideoTrackAdapterTest instantiates a ChildProcess which
registers a global TaskScheduler. To allow CONTINUE_ON_SHUTDOWN
tasks to continue running, ~ChildProcess does not clear that
global TaskScheduler. This is problematic when another test tries
to register TaskScheduler in the same process later on.

With this CL, PepperToVideoTrackAdapterTest::TearDown clears the
global TaskScheduler registered by ChildProcess.

BUG=682370

[fdoray, 2017-03-14 13:14:40]

Description was changed from

==========
home# Enter a description of the change.
Reset TaskScheduler during PepperToVideoTrackAdapterTest tear down.

PepperToVideoTrackAdapterTest instantiates a ChildProcess which
registers a global TaskScheduler. To allow CONTINUE_ON_SHUTDOWN
tasks to continue running, ~ChildProcess does not clear that
global TaskScheduler. This is problematic when another test tries
to register TaskScheduler in the same process later on.

With this CL, PepperToVideoTrackAdapterTest::TearDown clears the
global TaskScheduler registered by ChildProcess.

BUG=682370
==========

to

==========
Reset TaskScheduler during PepperToVideoTrackAdapterTest tear down.

PepperToVideoTrackAdapterTest instantiates a ChildProcess which
registers a global TaskScheduler. To allow CONTINUE_ON_SHUTDOWN
tasks to continue running, ~ChildProcess does not clear that
global TaskScheduler. This is problematic when another test tries
to register TaskScheduler in the same process later on.

With this CL, PepperToVideoTrackAdapterTest::TearDown clears the
global TaskScheduler registered by ChildProcess.

BUG=682370
==========

[fdoray, 2017-03-14 13:16:22]

fdoray@chromium.org changed reviewers:
+ mcasas@chromium.org

[fdoray, 2017-03-14 13:16:22]

PTAL

[chfremer, 2017-03-14 16:18:15]

On 2017/03/14 13:16:22, fdoray wrote:
> PTAL

See comment #6 in
https://bugs.chromium.org/p/chromium/issues/detail?id=682370#c6.
I don't think we should require every test that uses ChildProcess to manually
(and unobviously) have clean up like this.