Fix a crash in AVDA when dereferencing a null task runner

Fix a crash in AVDA when dereferencing a null task runner

Previously AVDAManager::StopThread() made the incorrect assumption that
the construction thread was running before using its task runner. Now
we only use the task runner when the the thread is running.

BUG=640806
TEST=run the webrtc.peerconnection benchmark

Committed: https://crrev.com/970f2b01f45ed574d12ffe9652191c7cf2c2f5fd
Cr-Commit-Position: refs/heads/master@{#414503}

[watk, 2016-08-24 23:24:31]

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

[commit-bot: I haz the power, 2016-08-24 23:25:20]

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

[watk, 2016-08-24 23:42:43]

watk@chromium.org changed reviewers:
+ dalecurtis@chromium.org

[watk, 2016-08-24 23:43:22]

Description was changed from

==========
Fix a crash in AVDA when dereferencing a null task runner

Previously AVDAManager::StopThread() made the incorrect assumption that
the construction thread was running before using its task runner. Now
we only use the task runner when the the thread is running.

BUG=640806
==========

to

==========
Fix a crash in AVDA when dereferencing a null task runner

Previously AVDAManager::StopThread() made the incorrect assumption that
the construction thread was running before using its task runner. Now
we only use the task runner when the the thread is running.

BUG=640806
TEST=run the webrtc.peerconnection benchmark
==========

[DaleCurtis, 2016-08-24 23:51:08]

lgtm

[watk, 2016-08-24 23:53:29]

The CQ bit was unchecked by watk@chromium.org

[watk, 2016-08-24 23:53:29]

The CQ bit was checked by watk@chromium.org

[commit-bot: I haz the power, 2016-08-24 23:53:42]

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, 2016-08-25 01:52:00]

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

[commit-bot: I haz the power, 2016-08-25 01:52:01]

Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[DaleCurtis, 2016-08-25 17:45:31]

The CQ bit was checked by dalecurtis@chromium.org

[commit-bot: I haz the power, 2016-08-25 17:46:12]

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, 2016-08-25 19:18:11]

Description was changed from

==========
Fix a crash in AVDA when dereferencing a null task runner

Previously AVDAManager::StopThread() made the incorrect assumption that
the construction thread was running before using its task runner. Now
we only use the task runner when the the thread is running.

BUG=640806
TEST=run the webrtc.peerconnection benchmark
==========

to

==========
Fix a crash in AVDA when dereferencing a null task runner

Previously AVDAManager::StopThread() made the incorrect assumption that
the construction thread was running before using its task runner. Now
we only use the task runner when the the thread is running.

BUG=640806
TEST=run the webrtc.peerconnection benchmark
==========

[commit-bot: I haz the power, 2016-08-25 19:18:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-25 19:21:52]

Description was changed from

==========
Fix a crash in AVDA when dereferencing a null task runner

Previously AVDAManager::StopThread() made the incorrect assumption that
the construction thread was running before using its task runner. Now
we only use the task runner when the the thread is running.

BUG=640806
TEST=run the webrtc.peerconnection benchmark
==========

to

==========
Fix a crash in AVDA when dereferencing a null task runner

Previously AVDAManager::StopThread() made the incorrect assumption that
the construction thread was running before using its task runner. Now
we only use the task runner when the the thread is running.

BUG=640806
TEST=run the webrtc.peerconnection benchmark

Committed: https://crrev.com/970f2b01f45ed574d12ffe9652191c7cf2c2f5fd
Cr-Commit-Position: refs/heads/master@{#414503}
==========

[commit-bot: I haz the power, 2016-08-25 19:21:53]

Patchset 1 (id:??) landed as
https://crrev.com/970f2b01f45ed574d12ffe9652191c7cf2c2f5fd
Cr-Commit-Position: refs/heads/master@{#414503}