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

sync/engine/syncer_proto_util_unittest.cc

Index: sync/engine/syncer_proto_util_unittest.cc
diff --git a/sync/engine/syncer_proto_util_unittest.cc b/sync/engine/syncer_proto_util_unittest.cc
index 81b25662894bdbb2ac7422e47c570cada4de8a8f..a5c1fd45b42351c433cc63f32c52d8474d818780 100644
--- a/sync/engine/syncer_proto_util_unittest.cc
+++ b/sync/engine/syncer_proto_util_unittest.cc
@@ -184,13 +184,9 @@ TEST(SyncerProtoUtil, NameExtractionTwoNames) {
 
 class SyncerProtoUtilTest : public testing::Test {
  public:
-  virtual void SetUp() {
-    dir_maker_.SetUp();
-  }
+  void SetUp() override { dir_maker_.SetUp(); }
 
-  virtual void TearDown() {
-    dir_maker_.TearDown();
-  }
+  void TearDown() override { dir_maker_.TearDown(); }
 
   syncable::Directory* directory() {
     return dir_maker_.directory();