Death to BlockSparseMatrixBase

Change-Id: I13b2b951297ae81bfab0a7b4991a791ed91d594c
diff --git a/internal/ceres/schur_complement_solver.cc b/internal/ceres/schur_complement_solver.cc
index 8afb121..9539c0d 100644
--- a/internal/ceres/schur_complement_solver.cc
+++ b/internal/ceres/schur_complement_solver.cc
@@ -58,7 +58,7 @@
 namespace internal {
 
 LinearSolver::Summary SchurComplementSolver::SolveImpl(
-    BlockSparseMatrixBase* A,
+    BlockSparseMatrix* A,
     const double* b,
     const LinearSolver::PerSolveOptions& per_solve_options,
     double* x) {