Separate selection editing from selection drawing
Summary:
Currently, we draw the selection immediately after it changes. Instead, update state and then draw out of state.
Also simplify and clean up a few things. Make all the inline endpoints return data in the same format.
Test Plan: Made various inline comments.
Reviewers: chad, ljalonen
Reviewed By: chad
CC: aran
Differential Revision: https://secure.phabricator.com/D5085