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

sql/meta_table_unittest.cc

Index: sql/meta_table_unittest.cc
diff --git a/sql/meta_table_unittest.cc b/sql/meta_table_unittest.cc
index 23b020fd5421aee9c0431bc1fede80b76ad30d40..e3ee2c6d5c3028db27b630f925066f6377b1cbb8 100644
--- a/sql/meta_table_unittest.cc
+++ b/sql/meta_table_unittest.cc
@@ -14,14 +14,12 @@ namespace {
 
 class SQLMetaTableTest : public testing::Test {
  public:
-  virtual void SetUp() {
+  void SetUp() override {
     ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
     ASSERT_TRUE(db_.Open(temp_dir_.path().AppendASCII("SQLMetaTableTest.db")));
   }
 
-  virtual void TearDown() {
-    db_.Close();
-  }
+  void TearDown() override { db_.Close(); }
 
   sql::Connection& db() { return db_; }