Implement accessibility in the omnibox shortcuts.

1. Makes the NTP tiles have a11y type of Button
2. Matches the a11y behavior of the NTP tiles for shortcuts.

Change-Id: I295f4b23776c0ede8209b86d02c4becbc6d3dd23
Reviewed-on: https://chromium-review.googlesource.com/c/1335597
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608761}

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

@@ -653,6 +653,9 @@ initWithContentService:(ntp_snippets::ContentSuggestionsService*)contentService
       BookmarkActionItem(), self.readingListItem, RecentTabsActionItem(),
       HistoryActionItem()
     ];
+    for (ContentSuggestionsMostVisitedActionItem* item in _actionButtonItems) {
+      item.accessibilityTraits = UIAccessibilityTraitButton;
+    }
   }
   return _actionButtonItems;
 }

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

@@ -142,6 +142,7 @@ ContentSuggestionsMostVisitedItem* ConvertNTPTile(
   suggestion.URL = tile.url;
   suggestion.source = tile.source;
   suggestion.titleSource = tile.title_source;
+  suggestion.accessibilityTraits = UIAccessibilityTraitButton;
 
   suggestion.suggestionIdentifier = [[ContentSuggestionIdentifier alloc] init];
   suggestion.suggestionIdentifier.IDInSection = tile.url.spec();

ios/chrome/browser/ui/omnibox/popup/shortcuts/collection_shortcut_cell.mm

@@ -20,6 +20,7 @@
     _tile.translatesAutoresizingMaskIntoConstraints = NO;
     [self.contentView addSubview:_tile];
     AddSameConstraints(self.contentView, _tile);
+    self.isAccessibilityElement = YES;
   }
   return self;
 }

ios/chrome/browser/ui/omnibox/popup/shortcuts/most_visited_shortcut_cell.mm

@@ -20,6 +20,7 @@
     _tile.translatesAutoresizingMaskIntoConstraints = NO;
     [self.contentView addSubview:_tile];
     AddSameConstraints(self.contentView, _tile);
+    self.isAccessibilityElement = YES;
   }
   return self;
 }

ios/chrome/browser/ui/omnibox/popup/shortcuts/shortcuts_view_controller.mm

@@ -173,6 +173,7 @@ const NSInteger kCollectionShortcutSection = 1;
     ShortcutsMostVisitedItem* item =
         self.displayedMostVisitedItems[indexPath.item];
     [self configureMostVisitedCell:cell withItem:item];
+    cell.accessibilityTraits = UIAccessibilityTraitButton;
     return cell;
   }
 
@@ -185,6 +186,7 @@ const NSInteger kCollectionShortcutSection = 1;
                                   "NTPCollectionShortcutType are supported";
     NTPCollectionShortcutType type = (NTPCollectionShortcutType)indexPath.item;
     [self configureCollectionShortcutCell:cell withCollection:type];
+    cell.accessibilityTraits = UIAccessibilityTraitButton;
     return cell;
   }
 
@@ -195,16 +197,21 @@ const NSInteger kCollectionShortcutSection = 1;
                         withItem:(ShortcutsMostVisitedItem*)item {
   [cell.tile.faviconView configureWithAttributes:item.attributes];
   cell.tile.titleLabel.text = item.title;
+  cell.accessibilityLabel = cell.tile.titleLabel.text;
 }
 
 - (void)configureCollectionShortcutCell:(CollectionShortcutCell*)cell
                          withCollection:(NTPCollectionShortcutType)type {
   cell.tile.titleLabel.text = TitleForCollectionShortcutType(type);
   cell.tile.iconView.image = ImageForCollectionShortcutType(type);
+  cell.accessibilityLabel = cell.tile.titleLabel.text;
+
   if (type == NTPCollectionShortcutTypeReadingList) {
     if (self.readingListBadgeValue > 0) {
       cell.tile.countLabel.text = [@(self.readingListBadgeValue) stringValue];
       cell.tile.countContainer.hidden = NO;
+      cell.accessibilityLabel = AccessibilityLabelForReadingListCellWithCount(
+          self.readingListBadgeValue);
     } else {
       cell.tile.countLabel.text = nil;
     }