What does the singing prole woman represent for Winston and for Julia?

The prole woman singing behind Charrington's apartment is symbolic to Julia and Winston because she represents a "sort of melancholy" happiness. It would seem she was perfectly content with her lot in life, trudging on through the days, even if her days were full of endless lines of laundry. Winston muses that no member of the party would sing so "alone", "spontaneously" and thinks that it would be a "dangerous eccentricity" (148). The prole woman might be a Sisyphus of sorts, from the Myth of Sisyphus, constantly struggling against an isolated and alienated existence, or perhaps trying to be happy in a dire situation. She is an example of someone trying to make the best out of her situation in life.