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

ios/chrome/browser/ui/settings/sync_create_passphrase_collection_view_controller.mm

 // Copyright 2015 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/settings/sync_create_passphrase_collection_view_controller.h"
 
 #import <UIKit/UIKit.h>
 
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
-#import "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 #import "ios/chrome/browser/ui/settings/cells/byo_textfield_item.h"
 #include "ios/chrome/grit/ios_strings.h"
 #import "ios/third_party/material_components_ios/src/components/Typography/src/MaterialTypography.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 using namespace ios_internal::sync_encryption_passphrase;
 
 @interface SyncCreatePassphraseCollectionViewController () {
-  base::scoped_nsobject<UITextField> confirmPassphrase_;
+  UITextField* confirmPassphrase_;
 }
 // Returns a confirm passphrase item.
 - (CollectionViewItem*)confirmPassphraseItem;
 @end
 
 @implementation SyncCreatePassphraseCollectionViewController
 
 - (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState {
   self = [super initWithBrowserState:browserState];
   if (self) {
     self.title =
         l10n_util::GetNSString(IDS_IOS_SYNC_ENCRYPTION_CREATE_PASSPHRASE);
     self.headerMessage = nil;
     self.footerMessage =
         l10n_util::GetNSString(IDS_IOS_SYNC_ENCRYPTION_PASSPHRASE_INFO),
     self.processingMessage =
         l10n_util::GetNSString(IDS_IOS_SYNC_PASSPHRASE_ENCRYPTING);
 
     [self loadModel];
   }
   return self;
 }
 
 #pragma mark - View lifecycle
 
 - (void)didReceiveMemoryWarning {
   [super didReceiveMemoryWarning];
   if (![self isViewLoaded]) {
-    confirmPassphrase_.reset();
+    confirmPassphrase_ = nil;
   }
 }
 
 - (void)viewDidDisappear:(BOOL)animated {
   [super viewDidDisappear:animated];
   if ([self isMovingFromParentViewController]) {
     [self unregisterTextField:self.confirmPassphrase];
   }
 }
 
 #pragma mark - SettingsRootCollectionViewController
 
 - (void)loadModel {
   [super loadModel];
   CollectionViewModel* model = self.collectionViewModel;
 
   NSInteger enterPassphraseIndex =
       [model indexPathForItemType:ItemTypeEnterPassphrase
                 sectionIdentifier:SectionIdentifierPassphrase]
           .item;
   [model insertItem:[self confirmPassphraseItem]
       inSectionWithIdentifier:SectionIdentifierPassphrase
                       atIndex:enterPassphraseIndex + 1];
 }
 
 #pragma mark - Items
 
 - (CollectionViewItem*)confirmPassphraseItem {
   if (!confirmPassphrase_) {
-    confirmPassphrase_.reset([[UITextField alloc] init]);
+    confirmPassphrase_ = [[UITextField alloc] init];
     [confirmPassphrase_ setFont:[MDCTypography body1Font]];
     [confirmPassphrase_ setSecureTextEntry:YES];
     [confirmPassphrase_ setBackgroundColor:[UIColor clearColor]];
     [confirmPassphrase_ setAutoresizingMask:UIViewAutoresizingFlexibleWidth];
     [confirmPassphrase_ setAutocorrectionType:UITextAutocorrectionTypeNo];
     [confirmPassphrase_
         setPlaceholder:l10n_util::GetNSString(
                            IDS_IOS_SYNC_CONFIRM_PASSPHRASE_LABEL)];
     [self registerTextField:confirmPassphrase_];
   }
 
-  BYOTextFieldItem* item = [[[BYOTextFieldItem alloc]
-      initWithType:ItemTypeConfirmPassphrase] autorelease];
+  BYOTextFieldItem* item =
+      [[BYOTextFieldItem alloc] initWithType:ItemTypeConfirmPassphrase];
   item.textField = confirmPassphrase_;
   return item;
 }
 
 #pragma mark UICollectionViewDelegate
 
 - (void)collectionView:(UICollectionView*)collectionView
     didSelectItemAtIndexPath:(NSIndexPath*)indexPath {
   [super collectionView:collectionView didSelectItemAtIndexPath:indexPath];
   NSInteger itemType =
@@ skipping 57 matching lines @@
 
 @end
 
 @implementation SyncCreatePassphraseCollectionViewController (UsedForTesting)
 
 - (UITextField*)confirmPassphrase {
   return confirmPassphrase_;
 }
 
 @end