Make sure <url>s are being serialized according to spec

Source/core/css/CSSMarkup.cpp

Index: Source/core/css/CSSMarkup.cpp
diff --git a/Source/core/css/CSSMarkup.cpp b/Source/core/css/CSSMarkup.cpp
index c9945a2f527cfe71d92db131bd68255a5820ef6f..03a3f8910f66615d3012fc57e9e9591d9bc987e8 100644
--- a/Source/core/css/CSSMarkup.cpp
+++ b/Source/core/css/CSSMarkup.cpp
@@ -263,21 +263,4 @@ String serializeString(const String& string)
     return builder.toString();
 }
 
-String serializeStringWithoutQuotations(const String& string)
-{
-    StringBuilder appendTo;
-    unsigned index = 0;
-    while (index < string.length()) {
-        UChar32 c = string.characterStartingAt(index);
-        index += U16_LENGTH(c);
-        if (c <= 0x1f)
-            serializeCharacterAsCodePoint(c, appendTo);
-        else if (c == 0x22 || c == 0x5c)
-            serializeCharacter(c, appendTo);
-        else
-            appendTo.append(c);
-    }
-    return appendTo.toString();
-}
-
 } // namespace blink