Standardize usage of virtual/override/final in remoting/

remoting/protocol/channel_multiplexer.h

Index: remoting/protocol/channel_multiplexer.h
diff --git a/remoting/protocol/channel_multiplexer.h b/remoting/protocol/channel_multiplexer.h
index 99a3112495127b9911ce35088e94614f0fda3996..74f268e63c833f05b2b3d90b694d64cd89934fae 100644
--- a/remoting/protocol/channel_multiplexer.h
+++ b/remoting/protocol/channel_multiplexer.h
@@ -21,12 +21,12 @@ class ChannelMultiplexer : public StreamChannelFactory {
   // |factory| is used to create the channel upon which to multiplex.
   ChannelMultiplexer(StreamChannelFactory* factory,
                      const std::string& base_channel_name);
-  virtual ~ChannelMultiplexer();
+  ~ChannelMultiplexer() override;
 
   // StreamChannelFactory interface.
-  virtual void CreateChannel(const std::string& name,
-                             const ChannelCreatedCallback& callback) override;
-  virtual void CancelChannelCreation(const std::string& name) override;
+  void CreateChannel(const std::string& name,
+                     const ChannelCreatedCallback& callback) override;
+  void CancelChannelCreation(const std::string& name) override;
 
  private:
   struct PendingChannel;