Suggested Articles can be dismissed

ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm

Index: ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm
diff --git a/ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm b/ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm
index 3fb509f14aefe104bec348c3038c1326ee9dde0e..83b87bd0222f60ec727b1cee7d6339d3b16b08a0 100644
--- a/ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm
+++ b/ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.mm
@@ -41,6 +41,8 @@ const NSTimeInterval kAnimationDuration = 0.35;
 @synthesize suggestionCommandHandler = _suggestionCommandHandler;
 @synthesize collectionUpdater = _collectionUpdater;
 
+#pragma mark - Public
+
 - (instancetype)initWithStyle:(CollectionViewControllerStyle)style
                    dataSource:(id<ContentSuggestionsDataSource>)dataSource {
   self = [super initWithStyle:style];
@@ -51,6 +53,19 @@ const NSTimeInterval kAnimationDuration = 0.35;
   return self;
 }
 
+- (void)dismissEntryAtIndexPath:(NSIndexPath*)indexPath {
+  if (!indexPath)
+    return;
+
+  [self.collectionView performBatchUpdates:^{
+    [self collectionView:self.collectionView
+        willDeleteItemsAtIndexPaths:@[ indexPath ]];

[lpromero, 2017/03/06 10:29:00]

Why do you call this? So that the item is removed from the model?
Should willDelete be outside performBatchUpdates and the deleteItems call be
inside?
Actually, why do you need the performBatchUpdates?

[gambard, 2017/03/06 12:16:00]

I use performBatchUpdates defensively because the UIColllectionView does not
support updating multiple cells in the same runloop.
I don't understand why willDelete (which delete items from the model) should be
outside? I think you were the one asking me to put it inside the
performBatchUpdate (in Reading List).

[lpromero, 2017/03/06 13:02:30]

Can -dismissEntryAtIndexPath: be called several times in a same turn of run
loop? Will calls be queued and run in their own turn?
Ah I remember:
https://github.com/material-components/material-components-ios/blob/620b5be11...
Thanks for the refresher!

[gambard, 2017/03/06 17:25:33]

For now it should not be called in the same turn of runloop. But in the future
maybe (and this API is public so I don't want to enforce something like "spin
the runloop between two call of this method").
By having performBatchUpdates, the updates will queue nicely if called during
the same turn of runloop.

+
+    [self.collectionView deleteItemsAtIndexPaths:@[ indexPath ]];
+  }
+                                completion:nil];
+}
+
 #pragma mark - UIViewController
 
 - (void)viewDidLoad {
@@ -197,8 +212,10 @@ const NSTimeInterval kAnimationDuration = 0.35;
   ContentSuggestionsArticleItem* articleItem =
       base::mac::ObjCCastStrict<ContentSuggestionsArticleItem>(touchedItem);
 
-  [self.suggestionCommandHandler displayContextMenuForArticle:articleItem
-                                                      atPoint:touchLocation];
+  [self.suggestionCommandHandler
+      displayContextMenuForArticle:articleItem
+                           atPoint:touchLocation
+                       atIndexPath:touchedItemIndexPath];
 }
 
 @end