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

sync/engine/apply_control_data_updates_unittest.cc

Index: sync/engine/apply_control_data_updates_unittest.cc
diff --git a/sync/engine/apply_control_data_updates_unittest.cc b/sync/engine/apply_control_data_updates_unittest.cc
index 7248d141815c36c8d7baab23904141715d98b7c7..7ed6bd4899f0604a3044f142743cc43b7cf3ed7e 100644
--- a/sync/engine/apply_control_data_updates_unittest.cc
+++ b/sync/engine/apply_control_data_updates_unittest.cc
@@ -35,16 +35,14 @@ class ApplyControlDataUpdatesTest : public ::testing::Test {
  public:
  protected:
   ApplyControlDataUpdatesTest() {}
-  virtual ~ApplyControlDataUpdatesTest() {}
+  ~ApplyControlDataUpdatesTest() override {}
 
-  virtual void SetUp() {
+  void SetUp() override {
     dir_maker_.SetUp();
     entry_factory_.reset(new TestEntryFactory(directory()));
   }
 
-  virtual void TearDown() {
-    dir_maker_.TearDown();
-  }
+  void TearDown() override { dir_maker_.TearDown(); }
 
   syncable::Directory* directory() {
     return dir_maker_.directory();