Fix reporting of uid state in battery stats.

Now that the activity manager keeps track of per-uid process states,
we can push that already rolled-up data into battery stats to directly
track the times in those states.

The problem with the reporting was actually that we weren't dealing
correctly with negative process states, which is now fixed.  (It was
interpreting them as FOREGROUND rather than not running.)

Also split out a number of new states -- TOP, FOREGROUND_SERVICE,
TOP_SLEEPING -- from FOREGROUND.  This should allow us to get a much
better idea of how much an app has been actively in use: TOP is when
it is directly visible to the user or in use by such, FOREGROUND_SERVICE
is when it is running in the background in a way the user is aware of.
Also when reporting these numbers, they are no longer added together as
reported but kept as separate times.

Change-Id: I6d307503a4b4ad5c0d5d49305ef63f8eb858e2c9