Remove KeyedObject interface (#7680)

patches/server/0342-PlayerDeathEvent-shouldDropExperience.patch

@@ -0,0 +1,19 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Shane Freeder <theboyetronic@gmail.com>
+Date: Tue, 24 Dec 2019 00:35:42 +0000
+Subject: [PATCH] PlayerDeathEvent#shouldDropExperience
+
+
+diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
+index 9441eae174c4441f7f4c9be69d39b415db01910c..910991b0c153a74d35cf097e0ac5a02559729a2e 100644
+--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
++++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
+@@ -883,7 +883,7 @@ public class ServerPlayer extends Player {
+             this.tellNeutralMobsThatIDied();
+         }
+         // SPIGOT-5478 must be called manually now
+-        this.dropExperience();
++        if (event.shouldDropExperience()) this.dropExperience(); // Paper - tie to event
+         // we clean the player's inventory after the EntityDeathEvent is called so plugins can get the exact state of the inventory.
+         if (!event.getKeepInventory()) {
+             // Paper start - replace logic