Too lazy to find the math right now, read the tooltip on "Shadow Mastery" tho,
http://www.wowhead.com/spell=87339 "Increase Shadow Spell damage by 25%" (30% after patch). Not "Increase Affliction Shadow Spell Damage" not "Increase Damage Over Time Shadow Spell Damage"... I don't know why so many people think Blizzard is out to trick them with tooltips.
If you want to prove it to yourself its fairly simple to do:
1. Go Destruction (they only have fire bonus damage) cast Shadowbolts
2. Go Affliction (they have +30% shadow bonus) cast Shadowbolts
3. Note Damage difference
4. ???
5. Profit
Do you also think that Demonic Knowledge
http://www.wowhead.com/spell=84740 the Demonology Mastery only effects Hand of Gul'dan, Hellfire, and Immolation Aura? Since only those 3 spells are actually in the Demonology tree after all...