Themes: Fix icon filters clamping to wrong values

Change-Id: Iab3cce465f8bdfd7c30a020fda254728349c5ebe
Themes: Make sure composed icon info is meaningful

We don't want to try and create a composed icon if the parts that
make up a composed icon are not valid or set.

Change-Id: I3d9e7432e4b351de9c0a4e662e028932ee7f08e2