Data usage API: any uid is accessible to system apps running in any user

This CL mostly affects Settings app as it can run in a user different
than UserHandle.OWNER. Since it is a system app it should have access
to all uid's data usage, regardless of which user it is currently running
in.

Bug: 19967498
Change-Id: I4a7787134d998457f7e2a1029183d44d9584083e
1 file changed