Add ascii() / latin1() / utf8() methods to AtomicString to avoid having to call string()

Source/wtf/text/WTFString.h

Index: Source/wtf/text/WTFString.h
diff --git a/Source/wtf/text/WTFString.h b/Source/wtf/text/WTFString.h
index 9b4d6119adf0de8a2bbbe286c00c222ae4f56094..7c2dffd226923a46e0e06d3c9b3aae7562624495 100644
--- a/Source/wtf/text/WTFString.h
+++ b/Source/wtf/text/WTFString.h
@@ -79,6 +79,12 @@ enum TrailingZerosTruncatingPolicy {
     TruncateTrailingZeros
 };
 
+enum UTF8ConversionMode {
+    LenientUTF8Conversion,
+    StrictUTF8Conversion,
+    StrictUTF8ConversionReplacingUnpairedSurrogatesWithFFFD
+};
+
 template<bool isSpecialCharacter(UChar), typename CharacterType>
 bool isAllSpecialCharacters(const CharacterType*, size_t);
 
@@ -183,14 +189,7 @@ public:
 
     CString ascii() const;
     CString latin1() const;
-
-    typedef enum {
-        LenientConversion,
-        StrictConversion,
-        StrictConversionReplacingUnpairedSurrogatesWithFFFD,
-    } ConversionMode;
-
-    CString utf8(ConversionMode = LenientConversion) const;
+    CString utf8(UTF8ConversionMode = LenientUTF8Conversion) const;
 
     UChar operator[](unsigned index) const
     {
@@ -680,6 +679,8 @@ WTF_EXPORT const String& emptyString();
 
 using WTF::CString;
 using WTF::KeepTrailingZeros;
+using WTF::StrictUTF8Conversion;
+using WTF::StrictUTF8ConversionReplacingUnpairedSurrogatesWithFFFD;
 using WTF::String;
 using WTF::emptyString;
 using WTF::append;