DesktopNativeWidgetAura adds itself as an ActivationChangeObserver for the content_window_. This is problematic with aura-mus as activation happens at the window associated with the WindowTreeHost, which is the parent of content_window_.
This causes WidgetTestInteractive.DisableViewDoesNotActivateWidget to fail because the widget is never told it loses activation so that state isn't stored correctly.
Comment 1 by e...@chromium.org
, Jan 4 2017