Introduce some convenience methods for handle rendering

Summary:
So I don't have to copy/paste everything again.

Used them at places I could find with my limited `grep` skills.

Test Plan: Visited hovercards, revision and tasks. No crashes.

Reviewers: epriestley, btrahan, chad

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5592