Fix for BrowserThreadTest tests

Most of BrowserThreadTest tests always fail (crash) the first time, and need to be retried separately (each test isolated). 

BrowserThreadImpl states need to be cleaned up between tests,
otherwise the subsequent tests will crash trying to reinitialize BrowserThreadImpl. 

This CL make sure that this is done correctly. 
BUG=697560
Review-Url: https://codereview.chromium.org/2721223004
Cr-Commit-Position: refs/heads/master@{#454321}
Committed: https://chromium.googlesource.com/chromium/src/+/61c9b8f29a2a7815f57b429725ce34922a828305

[dimaa1, 2017-03-01 21:42:17]

Description was changed from

==========
Fix for BrowserThreadTest tests

BUG=697560
==========

to

==========
Most of BrowserThreadTest tests always fail (crash) the first time, and need to
be retried separately (each test isolated). 

BrowserThreadImpl states need to be cleaned up between tests,
otherwise the subsequent tests will crash trying to reinitialize
BrowserThreadImpl. 

This CL make sure that this is done correctly. 
BUG=697560
==========

[dimaa1, 2017-03-01 21:49:32]

dimaa@chromium.org changed reviewers:
+ jam@chromium.org

[dimaa1, 2017-03-01 21:49:32]

Could you please review my CL?

[jam, 2017-03-02 01:07:05]

lgtm with nit

did you mean to remove chromium-reviews mailing list?

https://codereview.chromium.org/2721223004/diff/1/content/browser/browser_thr...
File content/browser/browser_thread_unittest.cc (right):

https://codereview.chromium.org/2721223004/diff/1/content/browser/browser_thr...
content/browser/browser_thread_unittest.cc:33: ui_thread_ = nullptr;
nit: put it in Teardown to match Setup, i.e. move this to line 48

[dimaa1, 2017-03-02 04:20:55]

dimaa@chromium.org changed reviewers:
+ chromium-reviews@chromium.org

[dimaa1, 2017-03-02 18:08:23]

The CQ bit was checked by dimaa@chromium.org

[dimaa1, 2017-03-02 18:08:23]

The patchset sent to the CQ was uploaded after l-g-t-m from jam@chromium.org
Link to the patchset: https://codereview.chromium.org/2721223004/#ps20001
(title: "Applied nit comment")

[commit-bot: I haz the power, 2017-03-02 18:08:37]

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, 2017-03-02 18:51:55]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1488478103579920,
"parent_rev": "3d6eaaf5186277676fbea8e191fc8067cd5a033a", "commit_rev":
"61c9b8f29a2a7815f57b429725ce34922a828305"}

[commit-bot: I haz the power, 2017-03-02 18:52:38]

Description was changed from

==========
Most of BrowserThreadTest tests always fail (crash) the first time, and need to
be retried separately (each test isolated). 

BrowserThreadImpl states need to be cleaned up between tests,
otherwise the subsequent tests will crash trying to reinitialize
BrowserThreadImpl. 

This CL make sure that this is done correctly. 
BUG=697560
==========

to

==========
Most of BrowserThreadTest tests always fail (crash) the first time, and need to
be retried separately (each test isolated). 

BrowserThreadImpl states need to be cleaned up between tests,
otherwise the subsequent tests will crash trying to reinitialize
BrowserThreadImpl. 

This CL make sure that this is done correctly. 
BUG=697560

Review-Url: https://codereview.chromium.org/2721223004
Cr-Commit-Position: refs/heads/master@{#454321}
Committed:
https://chromium.googlesource.com/chromium/src/+/61c9b8f29a2a7815f57b429725ce...
==========

[commit-bot: I haz the power, 2017-03-02 18:52:39]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/61c9b8f29a2a7815f57b429725ce...