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

Source/platform/text/TextBreakIteratorICU.cpp

Index: Source/platform/text/TextBreakIteratorICU.cpp
diff --git a/Source/platform/text/TextBreakIteratorICU.cpp b/Source/platform/text/TextBreakIteratorICU.cpp
index 7f31a38b7361623971ef0b2d59dfd5919a5e57a7..e1c0ea5b625ae74905e174cdb4b02fb6226d83a5 100644
--- a/Source/platform/text/TextBreakIteratorICU.cpp
+++ b/Source/platform/text/TextBreakIteratorICU.cpp
@@ -63,7 +63,7 @@ public:
         if (!iterator) {
             UErrorCode openStatus = U_ZERO_ERROR;
             bool localeIsEmpty = locale.isEmpty();
-            iterator = icu::BreakIterator::createLineInstance(localeIsEmpty ? icu::Locale(currentTextBreakLocaleID()) : icu::Locale(locale.string().utf8().data()), openStatus);
+            iterator = icu::BreakIterator::createLineInstance(localeIsEmpty ? icu::Locale(currentTextBreakLocaleID()) : icu::Locale(locale.utf8().data()), openStatus);
             // locale comes from a web page and it can be invalid, leading ICU
             // to fail, in which case we fall back to the default locale.
             if (!localeIsEmpty && U_FAILURE(openStatus)) {