Only add delete button once

Signal/src/ViewControllers/MediaPageViewController.swift

@@ -331,7 +331,7 @@ class MediaPageViewController: UIPageViewController, UIPageViewControllerDataSou
             return
         }
 
-        galleryRailView.configureCellViews(itemProvider: currentItem.album, focusedItem: currentItem)
+        galleryRailView.configureCellViews(itemProvider: currentItem.album, focusedItem: currentItem, cellViewDecoratorBlock: { _ in })
     }
 
     // MARK: Actions

SignalMessaging/ViewControllers/AttachmentApprovalViewController.swift

@@ -263,8 +263,7 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
         })
     }
 
-    func addDeleteIcon(cellViews: [GalleryRailCellView]) {
-        for cellView in cellViews {
+    func addDeleteIcon(cellView: GalleryRailCellView) {
         guard let attachmentItem = cellView.item as? SignalAttachmentItem else {
             owsFailDebug("attachmentItem was unexpectedly nil")
             return
@@ -286,7 +285,6 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
         button.autoPinEdge(toSuperviewMargin: .top)
         button.autoPinEdge(toSuperviewMargin: .trailing)
     }
-    }
 
     var pagerScrollView: UIScrollView?
     // This is kind of a hack. Since we don't have first class access to the superview's `scrollView`
@@ -428,8 +426,12 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
             return
         }
 
-        galleryRailView.configureCellViews(itemProvider: attachmentItemCollection, focusedItem: currentItem)
-        addDeleteIcon(cellViews: galleryRailView.cellViews)
+        let cellViewDecoratorBlock = { (cellView: GalleryRailCellView) in
+            self.addDeleteIcon(cellView: cellView)
+        }
+        galleryRailView.configureCellViews(itemProvider: attachmentItemCollection,
+                                           focusedItem: currentItem,
+                                           cellViewDecoratorBlock: cellViewDecoratorBlock)
 
         galleryRailView.isHidden = attachmentItemCollection.attachmentItems.count < 2
     }

SignalMessaging/Views/GalleryRailView.swift

@@ -118,7 +118,7 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
 
     // MARK: Public
 
-    public func configureCellViews(itemProvider: GalleryRailItemProvider?, focusedItem: GalleryRailItem?) {
+    public func configureCellViews(itemProvider: GalleryRailItemProvider?, focusedItem: GalleryRailItem?, cellViewDecoratorBlock: (GalleryRailCellView) -> Void) {
         let animationDuration: TimeInterval = 0.2
 
         guard let itemProvider = itemProvider else {
@@ -169,7 +169,7 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
             self.isHidden = false
         }
 
-        let cellViews = buildCellViews(items: itemProvider.railItems)
+        let cellViews = buildCellViews(items: itemProvider.railItems, cellViewDecoratorBlock: cellViewDecoratorBlock)
         self.cellViews = cellViews
         let stackView = UIStackView(arrangedSubviews: cellViews)
         stackView.axis = .horizontal
@@ -203,10 +203,11 @@ public class GalleryRailView: UIView, GalleryRailCellViewDelegate {
         return scrollView
     }()
 
-    private func buildCellViews(items: [GalleryRailItem]) -> [GalleryRailCellView] {
+    private func buildCellViews(items: [GalleryRailItem], cellViewDecoratorBlock: (GalleryRailCellView) -> Void) -> [GalleryRailCellView] {
         return items.map { item in
             let cellView = GalleryRailCellView()
             cellView.configure(item: item, delegate: self)
+            cellViewDecoratorBlock(cellView)
             return cellView
         }
     }