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

Source/platform/graphics/filters/DistantLightSource.h

Index: Source/platform/graphics/filters/DistantLightSource.h
diff --git a/Source/platform/graphics/filters/DistantLightSource.h b/Source/platform/graphics/filters/DistantLightSource.h
index ac288ad8ab76827c76c752d4510f058bcb4c2b3e..ecf3efdc85c810b4dc84d14ad1101a5c853f7a12 100644
--- a/Source/platform/graphics/filters/DistantLightSource.h
+++ b/Source/platform/graphics/filters/DistantLightSource.h
@@ -34,7 +34,7 @@ public:
         return adoptRef(new DistantLightSource(azimuth, elevation));
     }
 
-    virtual PassRefPtr<LightSource> create(const FloatPoint3D& scale, const FloatSize& offset) const override
+    PassRefPtr<LightSource> create(const FloatPoint3D& scale, const FloatSize& offset) const override
     {
         return adoptRef(new DistantLightSource(m_azimuth, m_elevation));
     }
@@ -42,10 +42,10 @@ public:
     float azimuth() const { return m_azimuth; }
     float elevation() const { return m_elevation; }
 
-    virtual bool setAzimuth(float) override;
-    virtual bool setElevation(float) override;
+    bool setAzimuth(float) override;
+    bool setElevation(float) override;
 
-    virtual TextStream& externalRepresentation(TextStream&) const override;
+    TextStream& externalRepresentation(TextStream&) const override;
 
 private:
     DistantLightSource(float azimuth, float elevation)