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

ios/chrome/browser/ui/authentication/authentication_ui_util.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.
 
 #import "ios/chrome/browser/ui/authentication/authentication_ui_util.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "components/strings/grit/components_strings.h"
 #include "ios/chrome/browser/ui/alert_coordinator/alert_coordinator.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace ios_internal {
 
 AlertCoordinator* ErrorCoordinator(NSError* error,
                                    ProceduralBlock dismissAction,
                                    UIViewController* viewController) {
   DCHECK(error);
 
   AlertCoordinator* alertCoordinator =
       ErrorCoordinatorNoItem(error, viewController);
 
@@ skipping 20 matching lines @@
         l10n_util::GetNSString(IDS_IOS_SYNC_ERROR_INTERNET_DISCONNECTED);
   } else if ([error.userInfo objectForKey:NSLocalizedDescriptionKey]) {
     errorMessage = [NSString stringWithFormat:@"%@ (%@ %" PRIdNS ")",
                                               error.localizedDescription,
                                               error.domain, error.code];
   } else {
     // If the error has no NSLocalizedDescriptionKey in its user info, then
     // |error.localizedDescription| contains the error domain and code.
     errorMessage = error.localizedDescription;
   }
-  AlertCoordinator* alertCoordinator = [[[AlertCoordinator alloc]
-      initWithBaseViewController:viewController
-                           title:title
-                         message:errorMessage] autorelease];
+  AlertCoordinator* alertCoordinator =
+      [[AlertCoordinator alloc] initWithBaseViewController:viewController
+                                                     title:title
+                                                   message:errorMessage];
   return alertCoordinator;
 }
 
 }  // namespace ios_internal