annotate: prepare ancestry context of workingfilectx _ancestrycontext is necessary for fast lookup of _changeid. Because we can't compute the ancestors from wctx, we skip to its parents. 'None' is not needed to be included in _ancestrycontext because it is used for a membership test of filelog revisions. repo: https://hg.mozilla.org/releases/mozilla-beta/#062e49bcb2da command: hg annotate -r 'wdir()' gfx/thebes/gfxWindowsPlatform.cpp before: 51.520 sec after: 1.780 sec