Add a missing header to context_impl.cc Change-Id: I7b6c564ac67926e91543a96bfd6362471de775c8
Ceres Solver is an open source C++ library for modeling and solving large, complicated optimization problems. It is a feature rich, mature and performant library which has been used in production at Google since 2010. Ceres Solver can solve two kinds of problems.
Please see ceres-solver.org for more information.