R1:698b7f9ea39c

Explicitly declare method/property visibility

Summary: Self-explanatory.

Test Plan: `arc lint`

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: hach-que, Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11278