Fix virtual/override/final usage in Source/platform/.

Source/platform/graphics/BitmapPattern.h

 // Copyright 2014 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 BitmapPattern_h
 #define BitmapPattern_h
 
 #include "platform/graphics/BitmapPatternBase.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT BitmapPattern : public BitmapPatternBase {
 public:
     static PassRefPtr<BitmapPattern> create(PassRefPtr<Image> tileImage, RepeatMode repeatMode)
     {
         return adoptRef(new BitmapPattern(tileImage, repeatMode));
     }
 
-    virtual ~BitmapPattern() { }
+    ~BitmapPattern() override {}
 
 protected:
-    virtual PassRefPtr<SkShader> createShader() override;
+    PassRefPtr<SkShader> createShader() override;
 
-    virtual SkImageInfo getBitmapInfo() override;
-    virtual void drawBitmapToCanvas(SkCanvas&, SkPaint&) override;
+    SkImageInfo getBitmapInfo() override;
+    void drawBitmapToCanvas(SkCanvas&, SkPaint&) override;
 
 private:
     BitmapPattern(PassRefPtr<Image>, RepeatMode);
 
     SkBitmap m_tileImage;
 };
 
 } // namespace
 
 #endif