Add missing virtual keyword for methods with OVERRIDE

Source/platform/graphics/filters/FEComponentTransfer.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 70 matching lines @@
 
     virtual TextStream& externalRepresentation(TextStream&, int indention) const;
 
 private:
     FEComponentTransfer(Filter*, const ComponentTransferFunction& redFunc, const ComponentTransferFunction& greenFunc,
         const ComponentTransferFunction& blueFunc, const ComponentTransferFunction& alphaFunc);
 
     virtual void applySoftware() OVERRIDE;
     virtual bool applySkia() OVERRIDE;
 
-    bool affectsTransparentPixels() OVERRIDE;
+    virtual bool affectsTransparentPixels() OVERRIDE;
 
     void getValues(unsigned char rValues[256], unsigned char gValues[256], unsigned char bValues[256], unsigned char aValues[256]);
 
     ComponentTransferFunction m_redFunc;
     ComponentTransferFunction m_greenFunc;
     ComponentTransferFunction m_blueFunc;
     ComponentTransferFunction m_alphaFunc;
 };
 
 } // namespace WebCore
 
 #endif // FEComponentTransfer_h