Update more platform classes to use OVERRIDE / FINAL when needed

Source/platform/graphics/filters/FEBlend.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 32 matching lines @@
 
     BlendModeType blendMode() const;
     bool setBlendMode(BlendModeType);
 
     void platformApplyGeneric(unsigned char* srcPixelArrayA, unsigned char* srcPixelArrayB, unsigned char* dstPixelArray,
                            unsigned colorArrayLength);
     void platformApplyNEON(unsigned char* srcPixelArrayA, unsigned char* srcPixelArrayB, unsigned char* dstPixelArray,
                            unsigned colorArrayLength);
     virtual PassRefPtr<SkImageFilter> createImageFilter(SkiaImageFilterBuilder*) OVERRIDE;
 
-    virtual TextStream& externalRepresentation(TextStream&, int indention) const;
+    virtual TextStream& externalRepresentation(TextStream&, int indention) const OVERRIDE;
 
 private:
     FEBlend(Filter*, BlendModeType);
 
     virtual void applySoftware() OVERRIDE;
     virtual bool applySkia() OVERRIDE;
 
     BlendModeType m_mode;
 };
 
 } // namespace WebCore
 
 #endif // FEBlend_h