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

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

 // Copyright 2016 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/handoff_collection_view_controller.h"
 
 #import "base/mac/foundation_util.h"
 #include "components/handoff/pref_names_ios.h"
 #include "components/prefs/pref_member.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #import "ios/chrome/browser/ui/collection_view/cells/MDCCollectionViewCell+Chrome.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_footer_item.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_switch_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.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 {
 
 typedef NS_ENUM(NSInteger, SectionIdentifier) {
   SectionIdentifierSwitch = kSectionIdentifierEnumZero,
   SectionIdentifierFooter,
 };
 
 typedef NS_ENUM(NSInteger, ItemType) {
   ItemTypeSwitch = kItemTypeEnumZero,
   ItemTypeFooter,
@@ skipping 26 matching lines @@
   return self;
 }
 
 #pragma mark - CollectionViewController
 
 - (void)loadModel {
   [super loadModel];
   CollectionViewModel* model = self.collectionViewModel;
 
   [model addSectionWithIdentifier:SectionIdentifierSwitch];
-  CollectionViewSwitchItem* switchItem = [[[CollectionViewSwitchItem alloc]
-      initWithType:ItemTypeSwitch] autorelease];
+  CollectionViewSwitchItem* switchItem =
+      [[CollectionViewSwitchItem alloc] initWithType:ItemTypeSwitch];
   switchItem.text =
       l10n_util::GetNSString(IDS_IOS_OPTIONS_ENABLE_HANDOFF_TO_OTHER_DEVICES);
   switchItem.on = _handoffEnabled.GetValue();
   [model addItem:switchItem toSectionWithIdentifier:SectionIdentifierSwitch];
 
   // The footer item must currently go into a separate section, to work around a
   // drawing bug in MDC.
   // TODO(crbug.com/650424) Use setFooter:forSectionWithIdentifier:.
   [model addSectionWithIdentifier:SectionIdentifierFooter];
-  CollectionViewFooterItem* footer = [[[CollectionViewFooterItem alloc]
-      initWithType:ItemTypeFooter] autorelease];
+  CollectionViewFooterItem* footer =
+      [[CollectionViewFooterItem alloc] initWithType:ItemTypeFooter];
   footer.text = l10n_util::GetNSString(
       IDS_IOS_OPTIONS_ENABLE_HANDOFF_TO_OTHER_DEVICES_DETAILS);
   [model addItem:footer toSectionWithIdentifier:SectionIdentifierFooter];
 }
 
 #pragma mark - UICollectionViewDataSource
 
 - (UICollectionViewCell*)collectionView:(UICollectionView*)collectionView
                  cellForItemAtIndexPath:(NSIndexPath*)indexPath {
   UICollectionViewCell* cell =
@@ skipping 64 matching lines @@
   }
 }
 
 #pragma mark - Private
 
 - (void)switchChanged:(UISwitch*)switchView {
   _handoffEnabled.SetValue(switchView.isOn);
 }
 
 @end