Support dropping of tabs into another apps as URLs

Author: tomasstrba

DuckDuckGo/TabBar/View/TabBarCollectionView.swift

@@ -32,9 +32,11 @@ class TabBarCollectionView: NSCollectionView {
         register(nib, forItemWithIdentifier: TabBarViewItem.identifier)
 
         // Register for the dropped object types we can accept.
-        registerForDraggedTypes([NSPasteboard.PasteboardType.string])
+        registerForDraggedTypes([.URL])
+        // Enable dragging items from our CollectionView to other applications.
+        setDraggingSourceOperationMask([.every], forLocal: false)
         // Enable dragging items within and into our CollectionView.
-        setDraggingSourceOperationMask(NSDragOperation.move, forLocal: false)
+        setDraggingSourceOperationMask([.move], forLocal: true)
     }
 
     func clearSelection() {

DuckDuckGo/TabBar/View/TabBarViewController.swift

@@ -370,9 +370,9 @@ extension TabBarViewController: NSCollectionViewDelegate {
     func collectionView(_ collectionView: NSCollectionView,
                         pasteboardWriterForItemAt indexPath: IndexPath) -> NSPasteboardWriting? {
         if let url = tabCollectionViewModel.tabCollection.tabs[indexPath.item].url {
-            return url.absoluteString as NSString
+            return url as NSURL
         } else {
-            return "" as NSString
+            return URL.emptyPage as NSURL
         }
     }