Work on sysui dependencies

One of the many problems with PhoneStatusBar is that it holds
dependencies for many other parts of SysUI. Fix this by creating
a static method of grabbing dependencies that are global to sysui
this cleans up a lot of chains of interdependence.

Also add easy way to inject mocks of these dependencies for the
purpose of testing.

Test: runtest systemui
Change-Id: Ia0e947faea62d15b665facada47ac9916c99f895