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

Source/core/html/MediaFragmentURIParser.cpp

Index: Source/core/html/MediaFragmentURIParser.cpp
diff --git a/Source/core/html/MediaFragmentURIParser.cpp b/Source/core/html/MediaFragmentURIParser.cpp
index f887a05f1630d12b8684ce9c39b245c8a066b265..70cd27fe98f0f9c1fb086bf831cfabd0f53dbc45 100644
--- a/Source/core/html/MediaFragmentURIParser.cpp
+++ b/Source/core/html/MediaFragmentURIParser.cpp
@@ -134,11 +134,11 @@ void MediaFragmentURIParser::parseFragments()
         //     name or value are not valid UTF-8 strings, then remove the name-value pair from the list.
         bool validUTF8 = true;
         if (!name.isEmpty()) {
-            name = name.utf8(String::StrictConversion).data();
+            name = name.utf8(StrictUTF8Conversion).data();
             validUTF8 = !name.isEmpty();
         }
         if (validUTF8 && !value.isEmpty()) {
-            value = value.utf8(String::StrictConversion).data();
+            value = value.utf8(StrictUTF8Conversion).data();
             validUTF8 = !value.isEmpty();
         }