Death to BlockSparseMatrixBase

Change-Id: I13b2b951297ae81bfab0a7b4991a791ed91d594c
diff --git a/internal/ceres/iterative_schur_complement_solver.cc b/internal/ceres/iterative_schur_complement_solver.cc
index 15e0bdc..d39d7db 100644
--- a/internal/ceres/iterative_schur_complement_solver.cc
+++ b/internal/ceres/iterative_schur_complement_solver.cc
@@ -62,7 +62,7 @@
 }
 
 LinearSolver::Summary IterativeSchurComplementSolver::SolveImpl(
-    BlockSparseMatrixBase* A,
+    BlockSparseMatrix* A,
     const double* b,
     const LinearSolver::PerSolveOptions& per_solve_options,
     double* x) {