Which one should it be? A close button at the corner or a third button in the middle (i.e. Share as Image, Share as text and Don't share)?

It should be an "x" button in the upper-right corner, similar to what we have in the "save-to-reading-list" dialog, or the "similar pages" dialog.

@Niedzielski, does this issue only concern the share preview dialog or have you noticed it elsewhere?

@Dbrant/@Nirzar, should a header bar be added like both the save-to-reading-list dialog and the content issues dialog have? Looks like @Nes has just added an 'X' close button so far:

@Nes, it looks like the close button will need to be a little further to the right (i.e., equal in distance from the top and right edges of the dialog).

@Nirzar , any other preliminary feedback?

@Mholloway , I think replacement of "X" is better now:)

@Mholloway, I didn't make a very comprehensive task in Phab. Let's consider this only for the share form and open up a separate phab for anything remaining that we notice.

I would suggest that we also add a padding of 8dp to the ScrollView but that can wait for another patch another day.

Change 312745 had a related patch set uploaded (by Nes):
ShareHandler: Add close button to large bottom sheets

https://gerrit.wikimedia.org/r/312745

Change 312745 merged by jenkins-bot:
ShareHandler: Add close button to large bottom sheets

https://gerrit.wikimedia.org/r/312745

Adding this to the sprint for design review. I'll leave the unplanned sprint work tag off for now since I'm not sure that one applies to work by volunteer devs.