Standardize usage of virtual/override/final in mojo/

mojo/services/test_service/test_service_impl.h

Index: mojo/services/test_service/test_service_impl.h
diff --git a/mojo/services/test_service/test_service_impl.h b/mojo/services/test_service/test_service_impl.h
index 379f02e050770da4b543c263237d3b1e38cc2e1b..904320b2667b6ebb0e271f5d61c5576e9cddfe7c 100644
--- a/mojo/services/test_service/test_service_impl.h
+++ b/mojo/services/test_service/test_service_impl.h
@@ -20,17 +20,16 @@ class TestServiceImpl : public InterfaceImpl<TestService> {
  public:
   TestServiceImpl(ApplicationConnection* connection,
                   TestServiceApplication* application);
-  virtual ~TestServiceImpl();
+  ~TestServiceImpl() override;
 
   // |TestService| methods:
-  virtual void OnConnectionEstablished() override;
-  virtual void OnConnectionError() override;
-  virtual void Ping(const mojo::Callback<void()>& callback) override;
-  virtual void ConnectToAppAndGetTime(
+  void OnConnectionEstablished() override;
+  void OnConnectionError() override;
+  void Ping(const mojo::Callback<void()>& callback) override;
+  void ConnectToAppAndGetTime(
       const mojo::String& app_url,
       const mojo::Callback<void(int64_t)>& callback) override;
-  virtual void StartTrackingRequests(
-      const mojo::Callback<void()>& callback) override;
+  void StartTrackingRequests(const mojo::Callback<void()>& callback) override;
 
  private:
   TestServiceApplication* const application_;