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

ios/chrome/browser/ui/settings/search_engine_settings_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/search_engine_settings_collection_view_controller.h"
 
 #include <memory>
 
-#import "base/ios/weak_nsobject.h"
 #include "base/mac/foundation_util.h"
-#import "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/search_engines/template_url_service.h"
 #include "components/search_engines/template_url_service_observer.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/search_engines/template_url_service_factory.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_text_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 #include "ios/chrome/grit/ios_strings.h"
 #import "ios/third_party/material_components_ios/src/components/CollectionCells/src/MaterialCollectionCells.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @interface SearchEngineSettingsCollectionViewController ()
 - (void)onChange;
 @end
 
 namespace {
 
 typedef NS_ENUM(NSInteger, SectionIdentifier) {
   SectionIdentifierSearchEngines = kSectionIdentifierEnumZero,
 };
 
 typedef NS_ENUM(NSInteger, ItemType) {
   ItemTypeSearchEnginesEngine = kItemTypeEnumZero,
 };
 
 // Observer used to reload the Search Engine collection view once the
 // TemplateURLService changes, either on first load or due to a
 // policy change.
 class SearchEngineObserver : public TemplateURLServiceObserver {
  public:
   SearchEngineObserver(SearchEngineSettingsCollectionViewController* owner,
                        TemplateURLService* urlService);
   ~SearchEngineObserver() override;
   void OnTemplateURLServiceChanged() override;
 
  private:
-  base::WeakNSObject<SearchEngineSettingsCollectionViewController> owner_;
+  __weak SearchEngineSettingsCollectionViewController* owner_;
   TemplateURLService* templateURLService_;  // weak
 };
 
 SearchEngineObserver::SearchEngineObserver(
     SearchEngineSettingsCollectionViewController* owner,
     TemplateURLService* urlService)
     : owner_(owner), templateURLService_(urlService) {
   templateURLService_->AddObserver(this);
 }
 
 SearchEngineObserver::~SearchEngineObserver() {
   templateURLService_->RemoveObserver(this);
 }
 
 void SearchEngineObserver::OnTemplateURLServiceChanged() {
-  base::scoped_nsobject<SearchEngineSettingsCollectionViewController>
-      strongOwner([owner_.get() retain]);
+  SearchEngineSettingsCollectionViewController* strongOwner = owner_;
   [strongOwner onChange];
 }
 
 }  // namespace
 
 @implementation SearchEngineSettingsCollectionViewController {
   TemplateURLService* templateURLService_;  // weak
   std::unique_ptr<SearchEngineObserver> observer_;
   // Prevent unnecessary notifications when we write to the setting.
   BOOL updatingBackend_;
@@ skipping 24 matching lines @@
   // Do not add any sections if there are no search engines.
   if (![values count]) {
     return;
   }
 
   [model addSectionWithIdentifier:SectionIdentifierSearchEngines];
   for (NSUInteger i = 0; i < values.count; i++) {
     NSString* value = values[i];
     BOOL checked = [value isEqualToString:[self currentValue]];
 
-    base::scoped_nsobject<CollectionViewTextItem> engine(
-        [[CollectionViewTextItem alloc]
-            initWithType:ItemTypeSearchEnginesEngine]);
+    CollectionViewTextItem* engine = [[CollectionViewTextItem alloc]
+        initWithType:ItemTypeSearchEnginesEngine];
     [engine setText:value];
     if (checked) {
       [engine setAccessoryType:MDCCollectionViewCellAccessoryCheckmark];
     }
     [model addItem:engine
         toSectionWithIdentifier:SectionIdentifierSearchEngines];
   }
 }
 
 #pragma mark UICollectionViewDelegate
@@ skipping 71 matching lines @@
   templateURLService_->SetUserSelectedDefaultSearchProvider(urls[index]);
   updatingBackend_ = NO;
 }
 
 - (void)onChange {
   if (!updatingBackend_)
     [self reloadData];
 }
 
 @end