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

ios/chrome/browser/ui/settings/settings_root_collection_view_controller_unittest.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/settings_root_collection_view_controller.h"
 
 #import <Foundation/Foundation.h>
 
-#import "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #import "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @interface TestSettingsRootCollectionViewController
     : SettingsRootCollectionViewController
 @property(nonatomic, readonly) NSMutableArray* items;
 - (void)reset;
 @end
 
 @implementation TestSettingsRootCollectionViewController {
-  base::scoped_nsobject<NSMutableArray> _items;
+  NSMutableArray* _items;
 }
 
 - (NSMutableArray*)items {
   if (!_items) {
-    _items.reset([[NSMutableArray alloc] init]);
+    _items = [[NSMutableArray alloc] init];
   }
-  return _items.get();
+  return _items;
 }
 
 - (void)reset {
-  _items.reset();
+  _items = nil;
 }
 
 - (void)loadModel {
   [super loadModel];
   if ([self.items count] > 0) {
     [self.collectionViewModel
         addSectionWithIdentifier:kSectionIdentifierEnumZero];
   }
   for (CollectionViewItem* item in self.items) {
     [self.collectionViewModel addItem:item
               toSectionWithIdentifier:kSectionIdentifierEnumZero];
   }
 }
 
 @end
 
 namespace {
 
 class SettingsRootCollectionViewControllerTest : public PlatformTest {
  public:
   SettingsRootCollectionViewControllerTest()
       : controller_([[TestSettingsRootCollectionViewController alloc]
             initWithStyle:CollectionViewControllerStyleDefault]) {
-    item1_.reset([[CollectionViewItem alloc] initWithType:kItemTypeEnumZero]);
-    item2_.reset(
-        [[CollectionViewItem alloc] initWithType:kItemTypeEnumZero + 10]);
+    item1_ = [[CollectionViewItem alloc] initWithType:kItemTypeEnumZero];
+    item2_ = [[CollectionViewItem alloc] initWithType:kItemTypeEnumZero + 10];
   }
 
  protected:
   void SetUp() override {
     PlatformTest::SetUp();
     [controller() reset];
   }
 
   TestSettingsRootCollectionViewController* controller() { return controller_; }
   CollectionViewItem* item1() { return item1_; }
   CollectionViewItem* item2() { return item2_; }
 
   id getCollectionViewItem(int section, int item) {
     return [controller().collectionViewModel
         itemAtIndexPath:[NSIndexPath indexPathForItem:item inSection:section]];
   }
 
   int numberOfSections() {
     return [controller().collectionViewModel numberOfSections];
   }
 
   int numberOfItems(int section) {
     return [controller().collectionViewModel numberOfItemsInSection:section];
   }
 
-  base::scoped_nsobject<TestSettingsRootCollectionViewController> controller_;
-  base::scoped_nsobject<CollectionViewItem> item1_;
-  base::scoped_nsobject<CollectionViewItem> item2_;
+  TestSettingsRootCollectionViewController* controller_;
+  CollectionViewItem* item1_;
+  CollectionViewItem* item2_;
 };
 
 TEST_F(SettingsRootCollectionViewControllerTest, Empty) {
   [controller() loadModel];
   EXPECT_EQ(0, numberOfSections());
 }
 
 TEST_F(SettingsRootCollectionViewControllerTest, ModelContents) {
   [controller().items addObjectsFromArray:@[ item1(), item2() ]];
   [controller() loadModel];
   EXPECT_EQ(1, numberOfSections());
   EXPECT_EQ(2, numberOfItems(0));
   EXPECT_EQ(item1(), getCollectionViewItem(0, 0));
   EXPECT_EQ(item2(), getCollectionViewItem(0, 1));
 }
 
 }  // namespace