Add the "virtual" keyword on method overrides that are missing it.

remoting/client/plugin/pepper_input_handler.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_CLIENT_PLUGIN_PEPPER_INPUT_HANDLER_H_
 #define REMOTING_CLIENT_PLUGIN_PEPPER_INPUT_HANDLER_H_
 
 #include "remoting/client/input_handler.h"
 
 struct PP_InputEvent_Character;
 struct PP_InputEvent_Key;
 struct PP_InputEvent_Mouse;
 
 namespace remoting {
 
 class PepperInputHandler : public InputHandler {
  public:
   PepperInputHandler(ClientContext* context,
                      protocol::ConnectionToHost* connection,
                      ChromotingView* view);
   virtual ~PepperInputHandler();
 
-  void Initialize();
+  virtual void Initialize();
 
   void HandleKeyEvent(bool keydown, const PP_InputEvent_Key& event);
   void HandleCharacterEvent(const PP_InputEvent_Character& event);
 
   void HandleMouseMoveEvent(const PP_InputEvent_Mouse& event);
   void HandleMouseButtonEvent(bool button_down,
                               const PP_InputEvent_Mouse& event);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PepperInputHandler);
 };
 
 }  // namespace remoting
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(remoting::PepperInputHandler);
 
 #endif  // REMOTING_CLIENT_PLUGIN_PEPPER_INPUT_HANDLER_H_