Constness in Context Added proper constness to Context getters. Change-Id: I0495cbe7ab0c9f50d4d9aa3d969507f117539bd8 Reviewed-on: https://swiftshader-review.googlesource.com/2983 Tested-by: Alexis Hétu <sugoi@google.com> Reviewed-by: Nicolas Capens <capn@google.com>