Porting update_icon improvements. Part 1.

code/game/objects/items/flamethrower.dm

@@ -27,6 +27,10 @@
 	var/igniter_type = /obj/item/assembly/igniter
 	trigger_guard = TRIGGER_GUARD_NORMAL
 
+/obj/item/flamethrower/ComponentInitialize()
+	. = ..()
+	AddElement(/datum/element/update_icon_updates_onmob)
+
 /obj/item/flamethrower/Destroy()
 	if(weldtool)
 		qdel(weldtool)
@@ -48,22 +52,17 @@
 	if(isturf(location)) //start a fire if possible
 		igniter.flamethrower_process(location)
 
+/obj/item/flamethrower/update_icon_state()
+	item_state = "flamethrower_[lit]"
 
-/obj/item/flamethrower/update_icon()
-	cut_overlays()
+/obj/item/flamethrower/update_overlays()
+	. = ..()
 	if(igniter)
-		add_overlay("+igniter[status]")
+		. += "+igniter[status]"
 	if(ptank)
-		add_overlay("+ptank")
+		. += "+ptank"
 	if(lit)
-		add_overlay("+lit")
-		item_state = "flamethrower_1"
-	else
-		item_state = "flamethrower_0"
-	if(ismob(loc))
-		var/mob/M = loc
-		M.update_inv_hands()
-	return
+		. += "+lit"
 
 /obj/item/flamethrower/afterattack(atom/target, mob/user, flag)
 	. = ..()