Move CS focus manager to its own thread

There's no good reason for it to be on the main thread, and it was
threatening to cause deadlocks. Moving to a separate thread.

Test: manual, verify no regressions
Change-Id: Ifc519ac778985e9f73a1325211693b4a9f5ba1e2
Merged-In: Ifc519ac778985e9f73a1325211693b4a9f5ba1e2