Fetch images for ContentSuggestions

ios/chrome/browser/ui/content_suggestions/content_suggestions_article_item.h

 // Copyright 2017 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.
 
 #ifndef IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_ARTICLE_ITEM_H_
 #define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_ARTICLE_ITEM_H_
 
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestion_identifier.h"
 #import "ios/third_party/material_components_ios/src/components/CollectionCells/src/MaterialCollectionCells.h"
 #include "url/gurl.h"
 
 namespace base {
 class Time;
 }
 
+@class ContentSuggestionsArticleItem;
+
+// Delegate for a ContentSuggestionsArticleItem.
+@protocol ContentSuggestionsArticleItemDelegate
+
+// Loads the image associated with this item.
+- (void)loadImageForArticleItem:(ContentSuggestionsArticleItem*)articleItem;
+
+@end
+
 // Item for an article in the suggestions.
 @interface ContentSuggestionsArticleItem
     : CollectionViewItem<ContentSuggestionIdentification>
 
 // Initialize an article with a |title|, a |subtitle|, an |image| and the |url|
 // to the full article. |type| is the type of the item.
 - (instancetype)initWithType:(NSInteger)type
                        title:(NSString*)title
                     subtitle:(NSString*)subtitle
-                       image:(UIImage*)image
+                    delegate:(id<ContentSuggestionsArticleItemDelegate>)delegate
                          url:(const GURL&)url NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)initWithType:(NSInteger)type NS_UNAVAILABLE;
 
 @property(nonatomic, copy, readonly) NSString* title;
 @property(nonatomic, strong) UIImage* image;
 @property(nonatomic, readonly, assign) GURL articleURL;
 @property(nonatomic, copy) NSString* publisher;
 @property(nonatomic, assign) base::Time publishDate;
 
+// Whether the image is being fetched. This property is set by the delegate.
+@property(nonatomic, assign) BOOL imageBeingFetched;
+
 @end
 
 // Corresponding cell for an article in the suggestions.
 @interface ContentSuggestionsArticleCell : MDCCollectionViewCell
 
 @property(nonatomic, readonly, strong) UILabel* titleLabel;
 @property(nonatomic, readonly, strong) UILabel* subtitleLabel;
 @property(nonatomic, readonly, strong) UIImageView* imageView;
 
 - (void)setPublisherName:(NSString*)publisherName date:(base::Time)publishDate;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_ARTICLE_ITEM_H_