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

Source/platform/graphics/filters/ReferenceFilter.h

Index: Source/platform/graphics/filters/ReferenceFilter.h
diff --git a/Source/platform/graphics/filters/ReferenceFilter.h b/Source/platform/graphics/filters/ReferenceFilter.h
index eddc1d35549b53ca50f1584e37fb27f8a550e00e..69271fde45ef80da7d9f223923107804b6590a07 100644
--- a/Source/platform/graphics/filters/ReferenceFilter.h
+++ b/Source/platform/graphics/filters/ReferenceFilter.h
@@ -49,10 +49,10 @@ public:
         return adoptRefWillBeNoop(new ReferenceFilter(scale));
     }
 
-    virtual ~ReferenceFilter();
+    ~ReferenceFilter() override;
     DECLARE_VIRTUAL_TRACE();
 
-    virtual IntRect sourceImageRect() const override { return IntRect(); };
+    IntRect sourceImageRect() const override { return IntRect(); };
 
     void setLastEffect(PassRefPtrWillBeRawPtr<FilterEffect>);
     FilterEffect* lastEffect() const { return m_lastEffect.get(); }