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

remoting/host/win/host_service.h

Index: remoting/host/win/host_service.h
diff --git a/remoting/host/win/host_service.h b/remoting/host/win/host_service.h
index 96cfff2d2d5ca881ca908fd2c660993764ba93a9..0ab78fee67b667f2aaa42a68e5c270296f0cb538 100644
--- a/remoting/host/win/host_service.h
+++ b/remoting/host/win/host_service.h
@@ -37,14 +37,14 @@ class HostService : public WtsTerminalMonitor {
   int Run();
 
   // WtsTerminalMonitor implementation
-  virtual bool AddWtsTerminalObserver(const std::string& terminal_id,
+  bool AddWtsTerminalObserver(const std::string& terminal_id,
                                       WtsTerminalObserver* observer) override;
-  virtual void RemoveWtsTerminalObserver(
+  void RemoveWtsTerminalObserver(
       WtsTerminalObserver* observer) override;
 
  private:
   HostService();
-  ~HostService();
+  ~HostService() override;
 
   // Notifies the service of changes in session state.
   void OnSessionChange(uint32 event, uint32 session_id);