Standardize usage of virtual/override/final specifiers.

ui/message_center/message_center_impl_unittest.cc

Index: ui/message_center/message_center_impl_unittest.cc
diff --git a/ui/message_center/message_center_impl_unittest.cc b/ui/message_center/message_center_impl_unittest.cc
index 6ce913122a7341cecb4488abf97c75a36f04eaf1..6f657e9ed45dfa2557ad37005f669285fd4833e7 100644
--- a/ui/message_center/message_center_impl_unittest.cc
+++ b/ui/message_center/message_center_impl_unittest.cc
@@ -27,7 +27,7 @@ class MessageCenterImplTest : public testing::Test,
  public:
   MessageCenterImplTest() {}
 
-  virtual void SetUp() override {
+  void SetUp() override {
     MessageCenter::Initialize();
     message_center_ = MessageCenter::Get();
     loop_.reset(new base::MessageLoop);
@@ -35,7 +35,7 @@ class MessageCenterImplTest : public testing::Test,
     closure_ = run_loop_->QuitClosure();
   }
 
-  virtual void TearDown() override {
+  void TearDown() override {
     run_loop_.reset();
     loop_.reset();
     message_center_ = NULL;