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

ios/chrome/browser/ui/settings/contextual_search_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/contextual_search_collection_view_controller.h"
 
 #include <memory>
 
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller_test.h"
 #import "ios/chrome/browser/ui/contextual_search/touch_to_search_permissions_mediator.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ios/web/public/test/test_web_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #import "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 class ContextualSearchCollectionViewControllerTest
     : public CollectionViewControllerTest {
  protected:
   ContextualSearchCollectionViewControllerTest() {
     TestChromeBrowserState::Builder browserStateBuilder;
     browser_state_ = browserStateBuilder.Build();
-    tts_permissions_.reset([[TouchToSearchPermissionsMediator alloc]
-        initWithBrowserState:browser_state_.get()]);
+    tts_permissions_ = [[TouchToSearchPermissionsMediator alloc]
+        initWithBrowserState:browser_state_.get()];
   }
 
-  CollectionViewController* NewController() override NS_RETURNS_RETAINED {
+  CollectionViewController* InstantiateController() override {
     return [[ContextualSearchCollectionViewController alloc]
         initWithPermissions:tts_permissions_];
   }
 
   web::TestWebThreadBundle thread_bundle_;
   std::unique_ptr<TestChromeBrowserState> browser_state_;
-  base::scoped_nsobject<TouchToSearchPermissionsMediator> tts_permissions_;
+  TouchToSearchPermissionsMediator* tts_permissions_;
 };
 
 TEST_F(ContextualSearchCollectionViewControllerTest,
        TestModelContextualSearchOff) {
   [tts_permissions_ setPreferenceState:TouchToSearch::DISABLED];
   CreateController();
   CheckController();
   EXPECT_EQ(2, NumberOfSections());
   EXPECT_EQ(1, NumberOfItemsInSection(0));
   CheckSwitchCellStateAndTitleWithId(NO, IDS_IOS_CONTEXTUAL_SEARCH_TITLE, 0, 0);
@@ skipping 13 matching lines @@
        TestModelContextualSearchUndecided) {
   [tts_permissions_ setPreferenceState:TouchToSearch::UNDECIDED];
   CreateController();
   EXPECT_EQ(2, NumberOfSections());
   EXPECT_EQ(1, NumberOfItemsInSection(0));
   CheckSwitchCellStateAndTitleWithId(YES, IDS_IOS_CONTEXTUAL_SEARCH_TITLE, 0,
                                      0);
 }
 
 }  // namespace