issue6528: implement _is_revision_affected using callback
The delta comming from a bundle/stream does not exists in the revlog yet, so we
will need other way to retrieve the same information.
To prepare for this we split the function to use callbacks in the core logic.
Differential Revision: https://phab.mercurial-scm.org/D11267
edition = "2018"
max_width = 79
wrap_comments = true
error_on_line_overflow = true