Remove unused includes of gflags and gtest Change-Id: Ie299a043c1095db4f85bd434f4bd9517e7641e06
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.