logd: worst uid record watermark part five

A regression that resulted in increased memory consumption for some
logging patterns because we rarely did merge or leading checks, and
age-out checking. On the last prune cycle, we reset for a full scan.

Add some comments describing the pruning processes.

Bug: 23327476
Bug: 23681639
Bug: 23685592
Change-Id: I22b0f339c9269b006831fda9cefe295a263ebb92
1 file changed
tree: 0b8853b574efcc30cb578d2f323a91b690cca0b3
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/