Standardize usage of virtual/override/final in base/

base/message_loop/message_pump_perftest.cc

Index: base/message_loop/message_pump_perftest.cc
diff --git a/base/message_loop/message_pump_perftest.cc b/base/message_loop/message_pump_perftest.cc
index 40550e17a3b15e58c115c4c726dd80e03250e5d1..9fca4653dbe2cb3f5bd622358ff6541910d0c27a 100644
--- a/base/message_loop/message_pump_perftest.cc
+++ b/base/message_loop/message_pump_perftest.cc
@@ -230,14 +230,13 @@ static void DoNothing() {
 class FakeMessagePump : public MessagePump {
  public:
   FakeMessagePump() {}
-  virtual ~FakeMessagePump() {}
+  ~FakeMessagePump() override {}
 
-  virtual void Run(Delegate* delegate) override {}
+  void Run(Delegate* delegate) override {}
 
-  virtual void Quit() override {}
-  virtual void ScheduleWork() override {}
-  virtual void ScheduleDelayedWork(
-      const TimeTicks& delayed_work_time) override {}
+  void Quit() override {}
+  void ScheduleWork() override {}
+  void ScheduleDelayedWork(const TimeTicks& delayed_work_time) override {}
 };
 
 class PostTaskTest : public testing::Test {