Use final effects to pass kraken damage upwards.

This should avoid the rest of still notorious crashes[1], and unlike
DracoOmega's ideas, doesn't turn krakens into a boring summoner-with-a-swarm
-of-pets we have too many examples of.

(Improvements to tentacle AI and connectivity are very welcome, I just
vehemently oppose making tentacles obstacles rather than parts of the kraken
itself.)

I did not yet purge a lot of no longer needed checks, to reduce possible
conflicts.

[1]. Even though such crashes are rare now, this is what killed my record
Abyss stress test run after over a week and umpteen million turns.

1 files changed, 14 insertions, 0 deletions

diff --git a/crawl-ref/source/fineff.h b/crawl-ref/source/fineff.h
index b2eb7f4969..a3bd370b24 100644
--- a/crawl-ref/source/fineff.h
+++ b/crawl-ref/source/fineff.h
@@ -121,6 +121,20 @@ protected:
     int blood;
 };
 
+class kraken_damage_fineff : public final_effect
+{
+public:
+    kraken_damage_fineff(const actor *attack, const actor *defend, int dam)
+        : final_effect(attack, defend, coord_def()), damage(dam)
+    {
+    }
+    bool mergeable(const final_effect &a) const;
+    void merge(const final_effect &a);
+    void fire();
+protected:
+    int damage;
+};
+
 void fire_final_effects();
 
 #endif