What is correct vapour barrier method for bathroom ceiling in a bungalow in Canada
Most of the time in a house in Canada you would have 6-10mil plastic over the drywall in the ceiling.

However the answer isn't that easy and the vapor barrier isn't needed for sure.  

It also depends on the type of insulation that you have (faced or not), what other types of barriers are installed in your attic, and really what is on the rest of your house.  

So from this picture I would get a ladder and look at what was in the next room on the ceiling.  I would do the same thing.  

My personal opinion... is that I don't like a vapor barrier in the attic above a bathroom.  Unless you paint the hell out of your ceiling (which I do for bathrooms including two coats of Killz oil based primer) water will get into the drywall.  It might after 4 coats too...  So I want that water to be able to escape, not be trapped in a vapor barrier.