It's absolutely stupid to ask candidate to work in uncomfortable environment (without favorite editor/IDE) and expect to see full potential of this developer.
Even if Google have some internal langs, even if this particular developer will have to work with them time to time, developer will spend some time to get used to it and become comfortable (more or less), not like in the interview.
For more absurd, ask them to dictate their code.
All my anger here is not pointed to you as interviewer, although I see some try to defend this style of interviewing with argument about "internal langs". Google invest a lot into IDE support of their home-made langs (Go, Dart), so I doubt it's a valid point.