Currently vertex paint doesn't draw at all
Grouping vertex & weight paint since they use the same code-paths for drawing.
For the records, it's "working" for blender internal (rB1129fd1c51e59d63e2f9a9b31cd2e873fef17b37) but not for the draw manager.
@Luca Rood (LucaRood) is this finished?
Oh yeah, forgot to close. There are still some possible optimizations, but it is all working, so this is finished.