chromeos: gets more ash_unittests working with single-process mash

The OverviewButtonTrayTests need to set the keyboard devices *after*
AshTestBase::SetUp() is called. This is is important in single-process mash
as Ash is the one creating the Env that the keyboard devices us. In
non-single-process-mash AshTestSuite is creating the Env these tests use.

The case ShellTest2.DontCrashWhenWindowDeleted is exercising is different
enough for single-process mash that I created a separate test.

Adding NOPRESUBMIT=true as this bot passed the trybots, and we're ok with
this test including Env::GetInstance().

NOPRESUBMIT=true

BUG=847992
TEST=test only changes

Change-Id: I0543db96ca9aa910340360d8da3e6aafcda34d7f
Reviewed-on: https://chromium-review.googlesource.com/1174978
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583161}
2 files changed