[ObjC ARC] Converts components/translate/ios/browser:browser to ARC.

components/translate/ios/browser/js_language_detection_manager.mm

Index: components/translate/ios/browser/js_language_detection_manager.mm
diff --git a/components/translate/ios/browser/js_language_detection_manager.mm b/components/translate/ios/browser/js_language_detection_manager.mm
index aa3384754ecda415f9f325399b622ac77794e0f3..822b896959b88b203dc193fc1c23870a77a58363 100644
--- a/components/translate/ios/browser/js_language_detection_manager.mm
+++ b/components/translate/ios/browser/js_language_detection_manager.mm
@@ -5,10 +5,13 @@
 #import "components/translate/ios/browser/js_language_detection_manager.h"
 
 #include "base/callback.h"
-#include "base/mac/scoped_nsobject.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace language_detection {
 // Note: This should stay in sync with the constant in language_detection.js.
 const size_t kMaxIndexChars = 65535;