Adding close button in SigninPromoView

ios/chrome/browser/ui/bookmarks/bookmark_folder_collection_view.mm

Index: ios/chrome/browser/ui/bookmarks/bookmark_folder_collection_view.mm
diff --git a/ios/chrome/browser/ui/bookmarks/bookmark_folder_collection_view.mm b/ios/chrome/browser/ui/bookmarks/bookmark_folder_collection_view.mm
index 4a6fd16c6ca1f8b7bc62635c4d6827d290d7e6f6..740083cbc09a02227fed397cf8fa587d170d6e7c 100644
--- a/ios/chrome/browser/ui/bookmarks/bookmark_folder_collection_view.mm
+++ b/ios/chrome/browser/ui/bookmarks/bookmark_folder_collection_view.mm
@@ -414,6 +414,10 @@ CGSize PreferredCellSizeForWidth(UICollectionViewCell* cell, CGFloat width) {
       signinPromoCell.signinPromoView.sendChromeCommand = YES;
       [[_signinPromoViewMediator createConfigurator]
           configureSigninPromoView:signinPromoCell.signinPromoView];
+      [signinPromoCell.signinPromoView.dismissButton
+                 addTarget:self

[lpromero, 2017/05/02 16:46:04]

I don't think it's an issue in your case, but conceptually, if the cell was
reused, would you be added twice (and thus called twice) when someone presses
the button? Should you remove yourself as a target at some point, or in
BookmarkSigninPromoCell's prepareForReuse, should you remove all targets?

[jlebel, 2017/05/03 12:41:14]

Done.

+                    action:@selector(dismissSigninPromo:)
+          forControlEvents:UIControlEventTouchUpInside];
       return signinPromoCell;
     } else {
       BookmarkPromoCell* promoCell = [self.collectionView
@@ -517,6 +521,10 @@ CGSize PreferredCellSizeForWidth(UICollectionViewCell* cell, CGFloat width) {
   }
 }
 
+- (void)dismissSigninPromo:(id)unused {
+  [self.delegate bookmarkCollectionViewDismissPromo:self];
+}
+
 #pragma mark - BookmarkPromoCellDelegate
 
 - (void)bookmarkPromoCellDidTapSignIn:(BookmarkPromoCell*)bookmarkPromoCell {