Range-based for loop saves the end iterator by assigning it to a
variable, so the iterator class needs to have a copy constructor at
least on some C++ compiler implementations.

The issue got introduced by a chain of three commits, so it's better to
just fix the issue rather than revert them all.

TEST=build on Windows

Change-Id: Ib6d8d7e97559838eaac44279454197445535f256
Reviewed-on: https://chromium-review.googlesource.com/309723
Tryjob-Request: Olli Etuaho <oetuaho@nvidia.com>
Tested-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>