Add missing virtual destructors to matrix adapters

Change-Id: Ieb0e67fbc9042410a6ae63e7cf0f96cc90603829

internal/ceres/schur_complement_solver.cc

diff --git a/internal/ceres/schur_complement_solver.cc b/internal/ceres/schur_complement_solver.cc
index da52b78..4e47837 100644
--- a/internal/ceres/schur_complement_solver.cc
+++ b/internal/ceres/schur_complement_solver.cc
@@ -68,6 +68,8 @@
       const BlockRandomAccessSparseMatrix& m)
       : m_(m) {}
 
+  virtual ~BlockRandomAccessSparseMatrixAdapter() final {}
+
   void RightMultiply(const Vector& x, Vector& y) final {
     m_.SymmetricRightMultiply(x.data(), y.data());
   }
@@ -83,6 +85,8 @@
       const BlockRandomAccessDiagonalMatrix& m)
       : m_(m) {}
 
+  virtual ~BlockRandomAccessDiagonalMatrixAdapter() final {}
+
   // y = y + Ax;
   void RightMultiply(const Vector& x, Vector& y) final {
     m_.RightMultiply(x.data(), y.data());