Update {virtual,override} to follow C++11 style in remoting.

remoting/host/gnubby_auth_handler_win.cc

Index: remoting/host/gnubby_auth_handler_win.cc
diff --git a/remoting/host/gnubby_auth_handler_win.cc b/remoting/host/gnubby_auth_handler_win.cc
index e24eb6b162f034645e4f1e775b61cd1a1f10794a..6b8bd644fd4ce1a651746ace8a23deda2d8189db 100644
--- a/remoting/host/gnubby_auth_handler_win.cc
+++ b/remoting/host/gnubby_auth_handler_win.cc
@@ -13,9 +13,9 @@ namespace {
 class GnubbyAuthHandlerWin : public GnubbyAuthHandler {
  private:
   // GnubbyAuthHandler interface.
-  virtual void DeliverClientMessage(const std::string& message) override;
-  virtual void DeliverHostDataMessage(int connection_id,
-                                      const std::string& data) const override;
+  void DeliverClientMessage(const std::string& message) override;
+  void DeliverHostDataMessage(int connection_id,
+                              const std::string& data) const override;
 
   DISALLOW_COPY_AND_ASSIGN(GnubbyAuthHandlerWin);
 };