Revert "Offload role manager work to background thread"

This reverts commit f105c93c.

Reason for revert: b/132974796#23 the offloaded thread will be holding a lock for a noticeable period of time and cause contention.

Bug: 132974796
Change-Id: Ic81a2e3ee7226266c8f97b606fc1a2834240f689