[PATCH] D31492: Add `addReplacement` interface in AtomicChange.

[Eric Liu via Phabricator via cfe-commits]

ioeric added a comment.

Please see comment from a previous patch (https://reviews.llvm.org/D27054?id=79099#inline-234270). Generally, `AtomicChange` is a higher level of abstraction than `Replacement`, and we don't want users to deal with `Replacement` and the related errors.


https://reviews.llvm.org/D31492