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

Source/platform/graphics/filters/PointLightSource.h

Index: Source/platform/graphics/filters/PointLightSource.h
diff --git a/Source/platform/graphics/filters/PointLightSource.h b/Source/platform/graphics/filters/PointLightSource.h
index 3ae6f9fc9bcf986e98644bdba08ff0fd5ba59e5b..f5806d735872639ab37b00e8ffb2add96f69f3eb 100644
--- a/Source/platform/graphics/filters/PointLightSource.h
+++ b/Source/platform/graphics/filters/PointLightSource.h
@@ -34,16 +34,16 @@ public:
         return adoptRef(new PointLightSource(position));
     }
 
-    virtual PassRefPtr<LightSource> create(const FloatPoint3D& scale, const FloatSize& offset) const override
+    PassRefPtr<LightSource> create(const FloatPoint3D& scale, const FloatSize& offset) const override
     {
         FloatPoint3D position(m_position.x() * scale.x() - offset.width(), m_position.y() * scale.y() - offset.height(), m_position.z() * scale.z());
         return adoptRef(new PointLightSource(position));
     }
 
     const FloatPoint3D& position() const { return m_position; }
-    virtual bool setPosition(const FloatPoint3D&) override;
+    bool setPosition(const FloatPoint3D&) override;
 
-    virtual TextStream& externalRepresentation(TextStream&) const override;
+    TextStream& externalRepresentation(TextStream&) const override;
 
 private:
     PointLightSource(const FloatPoint3D& position)