Did obrien implant the "dream"into winstons mind?

I am confused about the dream that winston had involving obrien.I am thinking that winston had attracted attention from the thought police in some way,and obrien began to study him.I think obrien implanted the dream into winston somehow to give winston a false sense of security towards himself in order to let winston get comfortable and give himself away,which he does.Personaly this whole ordeal took me by suprise,i belived that obrien was against big brother.