Namely: decltype(). Ideally we'd want C++17's template constructor
argument deduction, but instead use the C++11 solution: a factory
function. This enables using things such as lambdas in the container
argument.
Change-Id: Idba64d8069d15bbafe54cfdebe24b1fba1eb8d0a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>