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

components/translate/ios/browser/language_detection_controller.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/translate/ios/browser/language_detection_controller.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/time/time.h"
 #include "components/prefs/pref_member.h"
 #include "components/translate/core/common/translate_pref_names.h"
 #include "components/translate/core/language_detection/language_detection_util.h"
 #import "components/translate/ios/browser/js_language_detection_manager.h"
 #include "components/translate/ios/browser/string_clipping_util.h"
 #import "ios/web/public/url_scheme_util.h"
 #include "ios/web/public/web_state/web_state.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace translate {
 
 namespace {
 // Name for the UMA metric used to track text extraction time.
 const char kTranslateCaptureText[] = "Translate.CaptureText";
 // Prefix for the language detection javascript commands. Must be kept in sync
 // with language_detection.js.
 const char kCommandPrefix[] = "languageDetection";
 }
 
 LanguageDetectionController::LanguageDetectionController(
     web::WebState* web_state,
     JsLanguageDetectionManager* manager,
     PrefService* prefs)
     : web::WebStateObserver(web_state),
-      js_manager_([manager retain]),
+      js_manager_(manager),
       weak_method_factory_(this) {
   DCHECK(web::WebStateObserver::web_state());
   DCHECK(js_manager_);
   translate_enabled_.Init(prefs::kEnableTranslate, prefs);
   web_state->AddScriptCommandCallback(
       base::Bind(&LanguageDetectionController::OnTextCaptured,
                  base::Unretained(this)),
       kCommandPrefix);
 }
 
@@ skipping 92 matching lines @@
 
 void LanguageDetectionController::HistoryStateChanged() {
   StartLanguageDetection();
 }
 
 void LanguageDetectionController::WebStateDestroyed() {
   web_state()->RemoveScriptCommandCallback(kCommandPrefix);
 }
 
 }  // namespace translate