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

Source/wtf/text/TextCodecUTF16.h

Index: Source/wtf/text/TextCodecUTF16.h
diff --git a/Source/wtf/text/TextCodecUTF16.h b/Source/wtf/text/TextCodecUTF16.h
index d548f275db30cd06d382df29f9d2c360d8c41bda..cc2f37376a4908d89554e6f123f380fcd8135834 100644
--- a/Source/wtf/text/TextCodecUTF16.h
+++ b/Source/wtf/text/TextCodecUTF16.h
@@ -37,9 +37,9 @@ namespace WTF {
 
         TextCodecUTF16(bool littleEndian) : m_littleEndian(littleEndian), m_haveBufferedByte(false) { }
 
-        virtual String decode(const char*, size_t length, FlushBehavior, bool stopOnError, bool& sawError) override;
-        virtual CString encode(const UChar*, size_t length, UnencodableHandling) override;
-        virtual CString encode(const LChar*, size_t length, UnencodableHandling) override;
+        String decode(const char*, size_t length, FlushBehavior, bool stopOnError, bool& sawError) override;
+        CString encode(const UChar*, size_t length, UnencodableHandling) override;
+        CString encode(const LChar*, size_t length, UnencodableHandling) override;
 
     private:
         bool m_littleEndian;