Code review comment for lp:~robertcarr/mir/client-focus-notifications

219 +#include <initializer_list>
220 +#include <string>

Are these needed?

> 234 +protected
>
> line noise

+1. Just a nit, but there is no reason to add a protected block just for the deleted CopyAssign operations; we can put them under private.

> See "C++ Coding Standards" Guideline 51 (this isn't the guideline I consider wrong).

This also applies to

401 + ~Clog()
402 + {
403 + sink.unclog();
404 + }

since sink.unclog() can throw.