Notifications were never unregistered during unit tests.
Unit tests failure (DCHECK) due to objects over-retained by debug-only
consistency checks. The performSelector:withObject:afterDelay: retains
the object for at least 60 seconds causing object to live long enough
to catch the notification from a different test and thus DCHECK.
The failure is flaky because it is dependent on the order of
notification delivery.
The fix here is to disable consistency checks completely during unit
tests. Consistency checks are enabled in MainController which is not
part of this unit test.
BUG=518162
Review URL: https://codereview.chromium.org/
1298223003
Cr-Commit-Position: refs/heads/master@{#344258}