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

Source/platform/graphics/filters/FEDropShadow.h

Index: Source/platform/graphics/filters/FEDropShadow.h
diff --git a/Source/platform/graphics/filters/FEDropShadow.h b/Source/platform/graphics/filters/FEDropShadow.h
index aeb5ec67584e4f980f226fb033e8881d98689c29..ce7504f969882aa4e993936f0154489b51315f80 100644
--- a/Source/platform/graphics/filters/FEDropShadow.h
+++ b/Source/platform/graphics/filters/FEDropShadow.h
@@ -48,10 +48,10 @@ public:
     float shadowOpacity() const { return m_shadowOpacity; }
     void setShadowOpacity(float shadowOpacity) { m_shadowOpacity = shadowOpacity; }
 
-    virtual FloatRect mapRect(const FloatRect&, bool forward = true) override final;
+    FloatRect mapRect(const FloatRect&, bool forward = true) final;
 
-    virtual TextStream& externalRepresentation(TextStream&, int indention) const override;
-    virtual PassRefPtr<SkImageFilter> createImageFilter(SkiaImageFilterBuilder*) override;
+    TextStream& externalRepresentation(TextStream&, int indention) const override;
+    PassRefPtr<SkImageFilter> createImageFilter(SkiaImageFilterBuilder*) override;
 
 private:
     FEDropShadow(Filter*, float, float, float, float, const Color&, float);