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

Source/modules/webgl/OESStandardDerivatives.h

Index: Source/modules/webgl/OESStandardDerivatives.h
diff --git a/Source/modules/webgl/OESStandardDerivatives.h b/Source/modules/webgl/OESStandardDerivatives.h
index aef65bb7ccd329ae5c16a9c2b3e186d0a6e33c2b..6c1e7c73a970bc1e0544bc94f840d97a3ca01081 100644
--- a/Source/modules/webgl/OESStandardDerivatives.h
+++ b/Source/modules/webgl/OESStandardDerivatives.h
@@ -38,8 +38,8 @@ public:
     static bool supported(WebGLRenderingContextBase*);
     static const char* extensionName();
 
-    virtual ~OESStandardDerivatives();
-    virtual WebGLExtensionName name() const override;
+    ~OESStandardDerivatives() override;
+    WebGLExtensionName name() const override;
 
 private:
     explicit OESStandardDerivatives(WebGLRenderingContextBase*);