Fix virtual/override/final usage in Source/core/svg/.

Source/core/svg/graphics/SVGImage.h

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 62 matching lines @@
     void updateUseCounters(Document&) const;
 
     DisplayItemClient displayItemClient() const { return toDisplayItemClient(this); }
     String debugName() const { return "SVGImage"; }
 
 private:
     friend class AXLayoutObject;
     friend class SVGImageChromeClient;
     friend class SVGImageForContainer;
 
-    virtual ~SVGImage();
-
+    ~SVGImage() override;
 
     String filenameExtension() const override;
 
     void setContainerSize(const IntSize&) override;
     IntSize containerSize() const;
     bool usesContainerSize() const override { return true; }
     void computeIntrinsicDimensions(Length& intrinsicWidth, Length& intrinsicHeight, FloatSize& intrinsicRatio) override;
 
     bool dataChanged(bool allDataReceived) override;
 
@@ skipping 33 matching lines @@
         m_image->setImageObserver(m_observer);
     }
 private:
     Image* m_image;
     ImageObserver* m_observer;
 };
 
 }
 
 #endif // SVGImage_h