Remove unused text encoding quirks.

Source/wtf/text/TextEncoding.h

Index: Source/wtf/text/TextEncoding.h
diff --git a/Source/wtf/text/TextEncoding.h b/Source/wtf/text/TextEncoding.h
index 1e4aa7b3f683f8135a38cd9c8103a78086464b0b..058b3edfbb83af10315be442249d9aaaaa8d3bb1 100644
--- a/Source/wtf/text/TextEncoding.h
+++ b/Source/wtf/text/TextEncoding.h
@@ -58,14 +58,11 @@ public:
     // Applies Unicode NFC normalization, then encodes the normalized string.
     CString normalizeAndEncode(const String&, UnencodableHandling) const;
 
-    UChar backslashAsCurrencySymbol() const;
-
 private:
     bool isNonByteBasedEncoding() const;
     bool isUTF7Encoding() const;
 
     const char* m_name;
-    UChar m_backslashAsCurrencySymbol;
 };
 
 inline bool operator==(const TextEncoding& a, const TextEncoding& b) { return a.name() == b.name(); }