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

Source/platform/geometry/FloatPolygon.h

Index: Source/platform/geometry/FloatPolygon.h
diff --git a/Source/platform/geometry/FloatPolygon.h b/Source/platform/geometry/FloatPolygon.h
index 10f6cb8f5b430d548aa918f93ca7105f24b9a01a..c44498f87f9f9431293e31058477850f6c64a805 100644
--- a/Source/platform/geometry/FloatPolygon.h
+++ b/Source/platform/geometry/FloatPolygon.h
@@ -98,13 +98,13 @@ public:
 class PLATFORM_EXPORT FloatPolygonEdge : public VertexPair {
     friend class FloatPolygon;
 public:
-    virtual const FloatPoint& vertex1() const override
+    const FloatPoint& vertex1() const override
     {
         ASSERT(m_polygon);
         return m_polygon->vertexAt(m_vertexIndex1);
     }
 
-    virtual const FloatPoint& vertex2() const override
+    const FloatPoint& vertex2() const override
     {
         ASSERT(m_polygon);
         return m_polygon->vertexAt(m_vertexIndex2);