Collect and cache metadata, run hooks on changes.

Gerrit User 14985 75e7e43722 Update patch set 1 ... Patch Set 1: Code-Review+2 Workflow+1 we can submit a release note later Patch-set: 1 Label: Code-Review=+2 Label: Workflow=+1		2020-05-18 13:27:28 +00:00