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

ios/chrome/browser/ui/collection_view/collection_view_model.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_model.h"
 
 #include "base/logging.h"
-#include "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 typedef NSMutableArray<CollectionViewItem*> SectionItems;
 }
 
 @implementation CollectionViewModel {
   // Ordered list of section identifiers, one per section in the model.
-  base::scoped_nsobject<NSMutableArray<NSNumber*>> _sectionIdentifiers;
+  NSMutableArray<NSNumber*>* _sectionIdentifiers;
 
   // The lists of section items, one per section.
-  base::scoped_nsobject<NSMutableArray<SectionItems*>> _sections;
+  NSMutableArray<SectionItems*>* _sections;
 
   // Maps from section identifier to header and footer.
-  base::scoped_nsobject<NSMutableDictionary<NSNumber*, CollectionViewItem*>>
-      _headers;
-  base::scoped_nsobject<NSMutableDictionary<NSNumber*, CollectionViewItem*>>
-      _footers;
+  NSMutableDictionary<NSNumber*, CollectionViewItem*>* _headers;
+  NSMutableDictionary<NSNumber*, CollectionViewItem*>* _footers;
 }
 
 - (instancetype)init {
   if ((self = [super init])) {
-    _sectionIdentifiers.reset([[NSMutableArray alloc] init]);
-    _sections.reset([[NSMutableArray alloc] init]);
-    _headers.reset([[NSMutableDictionary alloc] init]);
-    _footers.reset([[NSMutableDictionary alloc] init]);
+    _sectionIdentifiers = [[NSMutableArray alloc] init];
+    _sections = [[NSMutableArray alloc] init];
+    _headers = [[NSMutableDictionary alloc] init];
+    _footers = [[NSMutableDictionary alloc] init];
   }
   return self;
 }
 
 #pragma mark Modification methods
 
 - (void)addSectionWithIdentifier:(NSInteger)sectionIdentifier {
   DCHECK_GE(sectionIdentifier, kSectionIdentifierEnumZero);
   DCHECK_EQ(static_cast<NSUInteger>(NSNotFound),
             [self internalSectionForIdentifier:sectionIdentifier]);
   [_sectionIdentifiers addObject:@(sectionIdentifier)];
 
-  base::scoped_nsobject<SectionItems> section([[SectionItems alloc] init]);
+  SectionItems* section = [[SectionItems alloc] init];
   [_sections addObject:section];
 }
 
 - (void)insertSectionWithIdentifier:(NSInteger)sectionIdentifier
                             atIndex:(NSUInteger)index {
   DCHECK_GE(sectionIdentifier, kSectionIdentifierEnumZero);
   DCHECK_EQ(static_cast<NSUInteger>(NSNotFound),
             [self internalSectionForIdentifier:sectionIdentifier]);
   DCHECK_LE(index, [_sections count]);
 
   [_sectionIdentifiers insertObject:@(sectionIdentifier) atIndex:index];
 
-  base::scoped_nsobject<SectionItems> section([[SectionItems alloc] init]);
+  SectionItems* section = [[SectionItems alloc] init];
   [_sections insertObject:section atIndex:index];
 }
 
 - (void)addItem:(CollectionViewItem*)item
     toSectionWithIdentifier:(NSInteger)sectionIdentifier {
   DCHECK_GE(item.type, kItemTypeEnumZero);
   NSInteger section = [self sectionForSectionIdentifier:sectionIdentifier];
   SectionItems* items = [_sections objectAtIndex:section];
   [items addObject:item];
 }
@@ skipping 250 matching lines @@
     }
     if (sectionItem.type == item.type) {
       indexInItemType++;
     }
   }
   DCHECK(found);
   return indexInItemType;
 }
 
 @end