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

ios/chrome/browser/ui/settings/about_chrome_collection_view_controller_unittest.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/about_chrome_collection_view_controller.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
-#import "base/mac/scoped_nsobject.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller_test.h"
 #import "ios/chrome/browser/ui/commands/UIKit+ChromeExecuteCommand.h"
 #import "ios/chrome/browser/ui/commands/open_url_command.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // An AboutChromeTableViewController that intercepts calls to
 // |chromeExecuteCommand:| in order to test the commands.
 @interface TestAboutChromeCollectionViewController
     : AboutChromeCollectionViewController
 
 // The intercepted chrome command.
 @property(nonatomic, readonly) OpenUrlCommand* command;
 
 @end
 
 @implementation TestAboutChromeCollectionViewController {
-  base::scoped_nsobject<OpenUrlCommand> command_;
+  OpenUrlCommand* command_;
 }
 
 - (IBAction)chromeExecuteCommand:(id)sender {
   DCHECK([sender isKindOfClass:[OpenUrlCommand class]]);
-  command_.reset([static_cast<OpenUrlCommand*>(sender) retain]);
+  command_ = static_cast<OpenUrlCommand*>(sender);
 }
 
 - (OpenUrlCommand*)command {
   return command_;
 }
 
 @end
 
 namespace {
 
 class AboutChromeCollectionViewControllerTest
     : public CollectionViewControllerTest {
  public:
-  CollectionViewController* NewController() override NS_RETURNS_RETAINED {
+  CollectionViewController* InstantiateController() override {
     return [[TestAboutChromeCollectionViewController alloc] init];
   }
 };
 
 TEST_F(AboutChromeCollectionViewControllerTest, TestModel) {
   CreateController();
   CheckController();
 
   EXPECT_EQ(2, NumberOfSections());
   EXPECT_EQ(3, NumberOfItemsInSection(0));
@@ skipping 21 matching lines @@
 
   [about_chrome_controller
                 collectionView:about_chrome_controller.collectionView
       didSelectItemAtIndexPath:[NSIndexPath indexPathForItem:2 inSection:0]];
   EXPECT_TRUE([about_chrome_controller command]);
   EXPECT_EQ(GURL(l10n_util::GetStringUTF8(IDS_IOS_PRIVACY_POLICY_URL)),
             [about_chrome_controller command].url);
 }
 
 }  // namespace