* Combat/Threat rewrite (PR #19930) prep work. Mostly refactors, and a compatibility layer on ThreatManager/HostileReference that allows scripts to be changed already.
(cherry picked from commit e2a1ccd118d129b96e09ff1a15ed0adb1d4a3897)
* Pet/Guardian AI hook re-organizing:
- Adjust OwnerAttacked/OwnerAttackedBy hooks on CreatureAI to fire for all owned units, not just player pets. This should allow guardians to more reliably recognize valid targets.
- Kill off the AttackedBy hook. While it was defined in CreatureAI.h as virtual, it was only ever invoked for player pets in specific situations. This makes it classic developer bait.
- Adjust PetAI to use DamageTaken instead of AttackedBy.
- Adjust behavior of AttackStart on PetAI to compensate.
(cherry picked from commit 1660bb7d27d6f42b49012a6b57e3c2b2eab20fd3)
- Changed self-accessor on GameObjectAI to "me", like UnitAI
- Moved all related functions to AI, now Unit and GameObject have the same function names with identical behaviour
- Remove "OnUpdate" from CreatureScript/GameObjectScript, was never used and we already have AI Update method
- Quest methods no longer return a bool, the return value was used to call the AI version if the ScriptMgr one returned false
- Implemented GameObjectAI::Destroyed hook (was never called), implemented Damaged method
- Rename OnStateChanged to OnLootStateChanged to reflect when it's really called, and created a new hook OnStateChanged that only gets called on GOState change
- Since the functions are now only getting called from AI, made GetAI methods full virtual. (CanSpawn method is anyways going to be used on creatures with AI)
(cherry picked from commit f913f3bb8977c127d200d5d4a608ab434b21bbcd)
Treeston