Remove unused Domain API.
Remove unused Domain API.

solvcon/solvcon,yungyuc/solvcon,yungyuc/solvcon,solvcon/solvcon,solvcon/solvcon,yungyuc/solvcon,yungyuc/solvcon,yungyuc/solvcon,solvcon/solvcon,solvcon/solvcon,yungyuc/solvcon,solvcon/solvcon