[ObjC ARC] Converts ios/chrome/browser/ui/util:util to ARC.

ios/chrome/browser/ui/util/i18n_string.mm

Index: ios/chrome/browser/ui/util/i18n_string.mm
diff --git a/ios/chrome/browser/ui/util/i18n_string.mm b/ios/chrome/browser/ui/util/i18n_string.mm
index 6aaf6816b943cb9df12b9ed63be8977548ee82a7..ebef79091e0ee87faf7729359e64c6105dbbab09 100644
--- a/ios/chrome/browser/ui/util/i18n_string.mm
+++ b/ios/chrome/browser/ui/util/i18n_string.mm
@@ -8,6 +8,10 @@
 #include "base/strings/string16.h"
 #include "base/strings/sys_string_conversions.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 NSString* AdjustStringForLocaleDirection(NSString* text) {
   base::string16 converted_text = base::SysNSStringToUTF16(text);
   bool has_changed =
@@ -15,5 +19,5 @@ NSString* AdjustStringForLocaleDirection(NSString* text) {
   if (has_changed) {
     return base::SysUTF16ToNSString(converted_text);
   }
-  return [[text copy] autorelease];
+  return [text copy];
 }