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

base/prefs/scoped_user_pref_update_unittest.cc

Index: base/prefs/scoped_user_pref_update_unittest.cc
diff --git a/base/prefs/scoped_user_pref_update_unittest.cc b/base/prefs/scoped_user_pref_update_unittest.cc
index dfe2074720d93fca0fa9da6ac7f60e04fba215fc..48e3dc4f7d425346a98785c7207ce78e32a481bb 100644
--- a/base/prefs/scoped_user_pref_update_unittest.cc
+++ b/base/prefs/scoped_user_pref_update_unittest.cc
@@ -16,10 +16,10 @@ using testing::Mock;
 class ScopedUserPrefUpdateTest : public testing::Test {
  public:
   ScopedUserPrefUpdateTest() : observer_(&prefs_) {}
-  virtual ~ScopedUserPrefUpdateTest() {}
+  ~ScopedUserPrefUpdateTest() override {}
 
  protected:
-  virtual void SetUp() {
+  void SetUp() override {
     prefs_.registry()->RegisterDictionaryPref(kPref);
     registrar_.Init(&prefs_);
     registrar_.Add(kPref, observer_.GetCallback());