Upstream Chrome on iOS source code [4/11].

ios/chrome/browser/ui/collection_view/cells/collection_view_item.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/cells/collection_view_item.h"
+
+#import "base/logging.h"
+#import "ios/third_party/material_components_ios/src/components/CollectionCells/src/MaterialCollectionCells.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation CollectionViewItem
+
+@synthesize type = _type;
+@synthesize cellClass = _cellClass;
+@synthesize accessibilityIdentifier = _accessibilityIdentifier;
+
+- (instancetype)initWithType:(NSInteger)type {
+  if ((self = [super init])) {
+    _type = type;
+    _cellClass = [MDCCollectionViewCell class];
+  }
+  return self;
+}
+
+- (instancetype)init {
+  NOTREACHED();
+  return nil;
+}
+
+- (void)setCellClass:(Class)cellClass {
+  DCHECK([cellClass isSubclassOfClass:[MDCCollectionViewCell class]]);
+  _cellClass = cellClass;
+}
+
+- (void)configureCell:(MDCCollectionViewCell*)cell {
+  DCHECK([cell class] == self.cellClass);
+  cell.accessibilityTraits = self.accessibilityTraits;
+  cell.accessibilityIdentifier = self.accessibilityIdentifier;
+}
+
+@end