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

ios/chrome/browser/ui/collection_view/cells/activity_indicator_cell.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/activity_indicator_cell.h"
+
+#import "ios/chrome/browser/ui/collection_view/cells/MDCCollectionViewCell+Chrome.h"
+#import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
+#import "ios/chrome/browser/ui/material_components/activity_indicator.h"
+#import "ios/third_party/material_components_ios/src/components/ActivityIndicator/src/MaterialActivityIndicator.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+const CGFloat kIndicatorSize = 32;
+
+@implementation ActivityIndicatorCell
+
+@synthesize activityIndicator = _activityIndicator;
+
+- (instancetype)initWithFrame:(CGRect)frame {
+  self = [super initWithFrame:frame];
+  if (self) {
+    _activityIndicator = [[MDCActivityIndicator alloc]
+        initWithFrame:CGRectMake(0, 0, kIndicatorSize, kIndicatorSize)];
+    _activityIndicator.cycleColors = ActivityIndicatorBrandedCycleColors();
+    [self.contentView addSubview:_activityIndicator];
+    _activityIndicator.translatesAutoresizingMaskIntoConstraints = NO;
+    [NSLayoutConstraint activateConstraints:@[
+      [_activityIndicator.topAnchor
+          constraintEqualToAnchor:self.contentView.topAnchor],
+      [_activityIndicator.bottomAnchor
+          constraintEqualToAnchor:self.contentView.bottomAnchor],
+      [_activityIndicator.leadingAnchor
+          constraintEqualToAnchor:self.contentView.leadingAnchor],
+      [_activityIndicator.trailingAnchor
+          constraintEqualToAnchor:self.contentView.trailingAnchor],
+    ]];
+    [_activityIndicator startAnimating];
+  }
+  return self;
+}
+
+@end