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

ios/chrome/browser/ui/collection_view/collection_view_controller_test.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/collection_view/collection_view_controller_test.h"
 
-#include "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
-#include "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_detail_item.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_footer_item.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_switch_item.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_text_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 
 #include "testing/gtest_mac.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 CollectionViewControllerTest::CollectionViewControllerTest() {}
 
 CollectionViewControllerTest::~CollectionViewControllerTest() {}
 
 void CollectionViewControllerTest::TearDown() {
   // Delete the controller before deleting other test variables, such as a
   // profile, to ensure things are cleaned up in the same order as in Chrome.
   controller_.reset();
   BlockCleanupTest::TearDown();
 }
@@ skipping 144 matching lines @@
   EXPECT_EQ(accessory_type,
             (MDCCollectionViewCellAccessoryType)[text_item accessoryType]);
 }
 
 void CollectionViewControllerTest::DeleteItem(
     int section,
     int item,
     ProceduralBlock completion_block) {
   NSIndexPath* index_path =
       [NSIndexPath indexPathForItem:item inSection:section];
-  base::WeakNSObject<CollectionViewController> weak_controller(controller_);
+  __weak CollectionViewController* weak_controller = controller_;
   void (^batch_updates)() = ^{
-    base::scoped_nsobject<CollectionViewController> strong_controller(
-        [weak_controller retain]);
+    CollectionViewController* strong_controller = weak_controller;
     if (!strong_controller)
       return;
     // Notify delegate to delete data.
     [strong_controller collectionView:[strong_controller collectionView]
           willDeleteItemsAtIndexPaths:@[ index_path ]];
 
     // Delete index paths.
     [[strong_controller collectionView]
         deleteItemsAtIndexPaths:@[ index_path ]];
   };
 
   void (^completion)(BOOL finished) = ^(BOOL finished) {
     // Notify delegate of deletion.
-    base::scoped_nsobject<CollectionViewController> strong_controller(
-        [weak_controller retain]);
+    CollectionViewController* strong_controller = weak_controller;
     if (!strong_controller)
       return;
     [strong_controller collectionView:[strong_controller collectionView]
            didDeleteItemsAtIndexPaths:@[ index_path ]];
     if (completion_block) {
       completion_block();
     }
   };
 
   [[controller_ collectionView] performBatchUpdates:batch_updates
                                          completion:completion];
 }