In <http://trac.webkit.org/changeset/212663>, a new dragging codepath was introduced that packages dragging information (e.g. drag image and pasteboard data) into a common DragItem struct. However, this is currently only used for Mac WK1. We should do the following for Mac WK2 and iOS (both WK1 and WK2): - Use DragItem to propagate drag information when initiating a drag - Use PasteboardWriterData to write data to the NSPasteboard/UIPasteboard/WebItemProviderPasteboard