Create ColorStateListDrawable

Previously, you could not use references to colors in places that
expected a Drawable. This new class, ColorStateListDrawable bridges the
gap by attaching a ColorStateList to a ColorDrawable, and hooks it into
resource loading wherever you might expect a Drawable.

Fixes: 18126411
Test: Unit tests to be added to CTS
Change-Id: I0ff9a089669da96e6b22b214f04d6726bc278152