Work around incomplete tinting support on L devices.

Background tinting implementation on L has a bug (fixed in
L MR1 onwards) which results in tinting not working in some cases.

Work around the bug by forcing state update on background drawable
on L devices.

Bug: 27674299
Change-Id: I40166c33a34c29bbfad43ca03d4897b52eb39f3b
4 files changed