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

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

 // Copyright 2013 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/content_settings_collection_view_controller.h"
 
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller_test.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ios/web/public/test/test_web_thread_bundle.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 class ContentSettingsCollectionViewControllerTest
     : public CollectionViewControllerTest {
  protected:
   void SetUp() override {
     CollectionViewControllerTest::SetUp();
     TestChromeBrowserState::Builder test_cbs_builder;
     chrome_browser_state_ = test_cbs_builder.Build();
   }
 
-  CollectionViewController* NewController() override NS_RETURNS_RETAINED {
+  CollectionViewController* InstantiateController() override {
     return [[ContentSettingsCollectionViewController alloc]
         initWithBrowserState:chrome_browser_state_.get()];
   }
 
  private:
   web::TestWebThreadBundle thread_bundle_;
   std::unique_ptr<TestChromeBrowserState> chrome_browser_state_;
 };
 
 TEST_F(ContentSettingsCollectionViewControllerTest, TestModel) {
   CreateController();
   CheckController();
   CheckTitleWithId(IDS_IOS_CONTENT_SETTINGS_TITLE);
 
   int expectedNumberOfItems = 2;
   ASSERT_EQ(1, NumberOfSections());
   EXPECT_EQ(expectedNumberOfItems, NumberOfItemsInSection(0));
   CheckDetailItemTextWithIds(IDS_IOS_BLOCK_POPUPS, IDS_IOS_SETTING_ON, 0, 0);
   CheckDetailItemTextWithIds(IDS_IOS_TRANSLATE_SETTING, IDS_IOS_SETTING_ON, 0,
                              1);
 }
 
 }  // namespace