It's not possible to paste file on Chrome on Mac

[Piotr Jasiun]

And it could be possible.

What Chrome gives, when I paste a file is DataTransfer (a.k.a. ClipboardData) object with an empty "files" property, but with 2 "items": first with a filename and the second with a file. It means it is possible to get a file from the second "item", on paste.

Unfortunately, when the upload plugin was implemented there was only one item on Chrome and only the first item is handled (see ​https://github.com/ckeditor/ckeditor-dev/blob/685fc7474fab779afe76edcf36011d2fb6bafab8/plugins/clipboard/plugin.js#L2545). If this line will be replaced with a loop it should be possible to get the file.

Note that on Windows pasted file is not available at all.

Also, note that now you do not need try-catch block there since items have a "kind" property which let you check if it is a file or a string.