D2462: util: add a file object proxy that can notify observers

[indygreg (Gregory Szorc)]

indygreg added inline comments.

INLINE COMMENTS

> lothiraldan wrote in util.py:535
> Could we define the `ours` set at the class level so an extension/subclass could easily update it if needed?

That's a good idea. I can do it as a follow-up. There are already a ton of commits in this series and I want to avoid more churn.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D2462

To: indygreg, #hg-reviewers
Cc: lothiraldan, mercurial-devel