R1:5eb4bc6ca960

Clean up more Quicksand

Summary: Creates a background that renders inside the Quicksand frame, through sorcery.

Test Plan: Turn on Quicksand, visit lots of pages. See correct background colors. This probably blows something up I'm not testing.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D16642