Try to improve PSS collection.

The goal is to collect PSS data from processes when they
are in as stable a state as possible.  We now have tables
for the durations to use for PSS collection based on
process state, and scheduling of collection is all driven
by process state changes.

Change-Id: I95e076f6971b9c093118e53dc8240fb3f5bad3b2
5 files changed