Standardize usage of virtual/override/final in remoting/

remoting/host/native_messaging/pipe_messaging_channel.h

Index: remoting/host/native_messaging/pipe_messaging_channel.h
diff --git a/remoting/host/native_messaging/pipe_messaging_channel.h b/remoting/host/native_messaging/pipe_messaging_channel.h
index fef1dac657bfed6be4670d724086d8754dbbb964..06fbf2aefd8a34b80ce3ca2ce074738f72b9d69e 100644
--- a/remoting/host/native_messaging/pipe_messaging_channel.h
+++ b/remoting/host/native_messaging/pipe_messaging_channel.h
@@ -35,11 +35,11 @@ class PipeMessagingChannel : public extensions::NativeMessagingChannel,
   // Constructs an object taking the ownership of |input| and |output|. Closes
   // |input| and |output| to prevent the caller from using them.
   PipeMessagingChannel(base::File input, base::File output);
-  virtual ~PipeMessagingChannel();
+  ~PipeMessagingChannel() override;
 
   // extensions::NativeMessagingChannel implementation.
-  virtual void Start(EventHandler* event_handler) override;
-  virtual void SendMessage(scoped_ptr<base::Value> message) override;
+  void Start(EventHandler* event_handler) override;
+  void SendMessage(scoped_ptr<base::Value> message) override;
 
  private:
   // Processes a message received from the client app.