This brush should be added to the set of brushes where we know which
vertices are going to be affected by the brush when starting the stroke.
This way we can limit the automasking only to those vertices instead of
flood filling the whole mesh from the active vertex.
All brushes that are not in this set will automask by flood filling the
mesh when starting the stroke. To improve this and make it work as most
users expect, we need a fast way to calculate topological distances on
high poly meshes.