The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3

commit ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3
Author: erg <erg@chromium.org>
Date: Wed Apr 12 20:54:53 2017

[views-mus] Prevent creating a native OzonePlatform in mus tests.

In the views_mus_unittests, we were always creating a native
OzonePlatform instance. Sometimes this was used instead of mus for the
test body. In most cases, it was accessed during test setup. This
modifies the test code to not build an implicit OzonePlatform.

In normal mus builds of chrome, we do not run with an OzonePlatform and
instead manually initialize some of the objects that OzonePlatform
owns. This ensures that AuraTestHelper doesn't create a local
implementation using the same detection method that Env uses to flip
into aura-mus mode.

BUG= 705037 ,  710195 ,  710939 

Review-Url: https://codereview.chromium.org/2807833002
Cr-Commit-Position: refs/heads/master@{#464147}

[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ash/system/status_area_widget_unittest.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/aura/env.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/aura/mus/os_exchange_data_provider_mus_unittest.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/aura/test/aura_test_helper.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/base/dragdrop/os_exchange_data_provider_factory.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/base/dragdrop/os_exchange_data_provider_factory.h
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/keyboard/keyboard_controller.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/views/BUILD.gn
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/views/mus/views_mus_test_suite.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/views/mus/views_mus_test_suite.h
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/views/test/widget_test_unittest.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/views/views_test_suite.cc
[modify] https://crrev.com/ac2e0aeea11a2641dfca4d1b192bd1641b5cd5d3/ui/views/views_test_suite.h

Adding this for single-process-mash to ensure we have coverage of all these tests.

I'm going to close this out as won't fix. The remaining tests are really exercising scenarios that mirror classic ash. This is useful to continue testing, but it's not something we need to create new tests for at this time yet.