Martin von Zweigbergk <martinvonz@google.com> [Sun, 17 Jun 2018 23:17:03 -0700] rev 38395
similar: use progress helper
A side-effect is that progress is now reported as 1 *before* we start
checking the first file. That seems to be how we do it in most places.
Also, the right topic is now closed.
Differential Revision: https://phab.mercurial-scm.org/D3796