If I understand well, what I call subdomains corresponds to your mvc, while what I call boundary_parts corresponds to your cf.
But when I use your code and then subdomains = mvc and boundary_parts = cf, I get nonsensical results.
For example a non-zero surface area assemble(1 * ds(12, domain=mesh)) returns 0 now, instead of the correct area. I suspect it’s because in my original code I have mesh = Mesh("file.xml") while in my new code I have mesh = Mesh(). I do not know which argument I can put inside the function Mesh(). I tried the XDMF file, but this returns an error. So I still don’t know how to make the full transition to XDMF.
Furthermore I am only able to reach that far on an Ubuntu machine, where dolfin has been compiled with hdf5 support. On Arch Linux (at home), I get an error message when I use your snippet codes as described in an earlier question here, and on the fenics support mailing list. I do not know how to compile dolfin with hdf5 support, it doesn’t do it by default even when the hdf5 package(s) are installed.