Add context menu for ContentSuggestions

ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.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/content_suggestions/content_suggestions_view_controller.h"
 
 #include "base/mac/foundation_util.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/collection_view/collection_view_model.h"
@@ skipping 43 matching lines @@
 
 #pragma mark - UIViewController
 
 - (void)viewDidLoad {
   [super viewDidLoad];
 
   _collectionUpdater.collectionViewController = self;
 
   self.collectionView.delegate = self;
   self.styler.cellStyle = MDCCollectionViewCellStyleCard;
+
+  UILongPressGestureRecognizer* longPressRecognizer =
+      [[UILongPressGestureRecognizer alloc]
+          initWithTarget:self
+                  action:@selector(handleLongPress:)];
+  longPressRecognizer.numberOfTouchesRequired = 1;
+  [self.collectionView addGestureRecognizer:longPressRecognizer];
 }
 
 #pragma mark - UICollectionViewDelegate
 
 - (void)collectionView:(UICollectionView*)collectionView
     didSelectItemAtIndexPath:(NSIndexPath*)indexPath {
   [super collectionView:collectionView didSelectItemAtIndexPath:indexPath];
 
   CollectionViewItem* item =
       [self.collectionViewModel itemAtIndexPath:indexPath];
@@ skipping 99 matching lines @@
                  }];
   }
 }
 
 - (void)openArticle:(CollectionViewItem*)item {
   ContentSuggestionsArticleItem* article =
       base::mac::ObjCCastStrict<ContentSuggestionsArticleItem>(item);
   [self.suggestionCommandHandler openURL:article.articleURL];
 }
 
+- (void)handleLongPress:(UILongPressGestureRecognizer*)gestureRecognizer {
+  if (self.editor.editing ||
+      gestureRecognizer.state != UIGestureRecognizerStateBegan) {
+    return;
+  }
+
+  CGPoint touchLocation =
+      [gestureRecognizer locationOfTouch:0 inView:self.collectionView];
+  NSIndexPath* touchedItemIndexPath =
+      [self.collectionView indexPathForItemAtPoint:touchLocation];
+  if (!touchedItemIndexPath ||
+      ![self.collectionViewModel hasItemAtIndexPath:touchedItemIndexPath]) {
+    // Make sure there is an item at this position.
+    return;
+  }
+  CollectionViewItem* touchedItem =

[stkhapugin, 2017/02/15 16:03:36]

nit: keep all code handling the *touch* here, and move the rest (lines 208 and
below) to a method that shows a context menu for CVItem. This will be useful in
case the context menu is triggered by something else, for example a "..."
button. 

[gambard, 2017/02/16 10:17:13]

The "..." will probably be handled at the cell level. I will keep it in mind.

+      [self.collectionViewModel itemAtIndexPath:touchedItemIndexPath];
+
+  if (touchedItem == [self.collectionViewModel
+                         headerForSection:touchedItemIndexPath.section] ||

[stkhapugin, 2017/02/15 16:03:36]

I'm not familiar with this API, is it possible that touched item is header?

[gambard, 2017/02/16 10:17:13]

Done.

+      [self.collectionUpdater contentSuggestionTypeForItem:touchedItem] !=
+          ContentSuggestionTypeArticle) {
+    // Only trigger context menu on articles.
+    return;
+  }
+
+  ContentSuggestionsArticleItem* articleItem =
+      base::mac::ObjCCastStrict<ContentSuggestionsArticleItem>(touchedItem);
+
+  [self.suggestionCommandHandler displayContextMenuForArticle:articleItem
+                                                      atPoint:touchLocation];
+}
+
 @end