8d044e8bc2
This introduces four generic thread that services can use in the system process: - Background: part of the framework for all processes, for work that is purely background (no timing constraint). - UI: for time-critical display of UI. - Foreground: normal foreground work. - IO: performing IO operations. I went through and moved services into these threads in the places I felt relatively comfortable about understanding what they are doing. There are still a bunch more we need to look at -- lots of networking stuff left, 3 or so different native daemon connectors which I didn't know how much would block, audio stuff, etc. Also updated Watchdog to be aware of and check these new threads, with a new API for other threads to also participate in this checking. Change-Id: Ie2f11061cebde5f018d7383b3a910fbbd11d5e11