The active player controls exactly 1 Dragon, and that Dragon is a creature.
That player casts a Dragon-check spell
https://scryfall.com/search?q=oracle...as+you+cast%22
, ​ and as part of that casting process, sacrifices
that player's Dragon to pay a mana ability's cost
https://scryfall.com/search?q=oracle...ture%3A+Add%22
and does not reveal a Dragon card from that player's hand.

Can that player time things so as to get the
"If you revealed a Dragon card or controlled a Dragon as you cast"
part?