Standardize usage of virtual/override/final specifiers in sql/.

sql/statement_unittest.cc

Index: sql/statement_unittest.cc
diff --git a/sql/statement_unittest.cc b/sql/statement_unittest.cc
index a140ee095c327445a0bb1b4ef2940ce6ce2f7276..38f1778d7361675dde3fcde4e17e6d4e8ffcfdfe 100644
--- a/sql/statement_unittest.cc
+++ b/sql/statement_unittest.cc
@@ -18,14 +18,12 @@ namespace {
 
 class SQLStatementTest : public testing::Test {
  public:
-  virtual void SetUp() {
+  void SetUp() override {
     ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
     ASSERT_TRUE(db_.Open(temp_dir_.path().AppendASCII("SQLStatementTest.db")));
   }
 
-  virtual void TearDown() {
-    db_.Close();
-  }
+  void TearDown() override { db_.Close(); }
 
   sql::Connection& db() { return db_; }