Collect and cache metadata, run hooks on changes.

Gerrit User 31828 c4f1000e89 Update patch set 1 ... Patch Set 1: Code-Review+1 Patch-set: 1 Reviewer: Gerrit User 31828 <31828@4a232e18-c5a9-48ee-94c0-e04e7cca6543> Label: Code-Review=+1		2021-07-14 06:07:12 +00:00