Standardize usage of virtual/override/final in mojo/

mojo/edk/system/dispatcher_unittest.cc

Index: mojo/edk/system/dispatcher_unittest.cc
diff --git a/mojo/edk/system/dispatcher_unittest.cc b/mojo/edk/system/dispatcher_unittest.cc
index d9d526d8e5bb79d31c0739b95efd171cf1d36bf4..b5a05d424c7759ffedde0d425c31617f58f77534 100644
--- a/mojo/edk/system/dispatcher_unittest.cc
+++ b/mojo/edk/system/dispatcher_unittest.cc
@@ -23,14 +23,14 @@ class TrivialDispatcher : public Dispatcher {
  public:
   TrivialDispatcher() {}
 
-  virtual Type GetType() const override { return kTypeUnknown; }
+  Type GetType() const override { return kTypeUnknown; }
 
  private:
   friend class base::RefCountedThreadSafe<TrivialDispatcher>;
-  virtual ~TrivialDispatcher() {}
+  ~TrivialDispatcher() override {}
 
-  virtual scoped_refptr<Dispatcher>
-  CreateEquivalentDispatcherAndCloseImplNoLock() override {
+  scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
+      override {
     lock().AssertAcquired();
     return scoped_refptr<Dispatcher>(new TrivialDispatcher());
   }
@@ -157,10 +157,10 @@ class ThreadSafetyStressThread : public base::SimpleThread {
     CHECK_LT(op_, DISPATCHER_OP_COUNT);
   }
 
-  virtual ~ThreadSafetyStressThread() { Join(); }
+  ~ThreadSafetyStressThread() override { Join(); }
 
  private:
-  virtual void Run() override {
+  void Run() override {
     event_->Wait();
 
     waiter_.Init();