Porting update_icon improvements. Part 1.

code/game/objects/items/tools/screwdriver.dm

@@ -45,13 +45,13 @@
 	if(prob(75))
 		pixel_y = rand(0, 16)
 
-/obj/item/screwdriver/update_icon()
+/obj/item/screwdriver/update_overlays()
+	. = ..()
 	if(!random_color) //icon override
 		return
-	cut_overlays()
 	var/mutable_appearance/base_overlay = mutable_appearance(icon, "screwdriver_screwybits")
 	base_overlay.appearance_flags = RESET_COLOR
-	add_overlay(base_overlay)
+	. += base_overlay
 
 /obj/item/screwdriver/worn_overlays(isinhands = FALSE, icon_file, style_flags = NONE)
 	. = list()

code/game/objects/items/tools/weldingtool.dm

@@ -40,24 +40,24 @@
 	reagents.add_reagent(/datum/reagent/fuel, max_fuel)
 	update_icon()
 
+/obj/item/weldingtool/ComponentInitialize()
+	. = ..()
+	AddElement(/datum/element/update_icon_updates_onmob)
 
-/obj/item/weldingtool/proc/update_torch()
+/obj/item/weldingtool/update_icon_state()
 	if(welding)
-		add_overlay("[initial(icon_state)]-on")
 		item_state = "[initial(item_state)]1"
 	else
 		item_state = "[initial(item_state)]"
 
-
-/obj/item/weldingtool/update_icon()
-	cut_overlays()
+/obj/item/weldingtool/update_overlays()
+	. = ..()
 	if(change_icons)
 		var/ratio = get_fuel() / max_fuel
 		ratio = CEILING(ratio*4, 1) * 25
-		add_overlay("[initial(icon_state)][ratio]")
-	update_torch()
-	return
-
+		. += "[initial(icon_state)][ratio]"
+	if(welding)
+		. += "[initial(icon_state)]-on"
 
 /obj/item/weldingtool/process()
 	switch(welding)
@@ -177,11 +177,6 @@
 	if(get_fuel() <= 0 && welding)
 		switched_on(user)
 		update_icon()
-		//mob icon update
-		if(ismob(loc))
-			var/mob/M = loc
-			M.update_inv_hands(0)
-
 		return 0
 	return 1
 

code/game/objects/items/tools/wirecutters.dm

@@ -40,13 +40,13 @@
 		add_atom_colour(wirecutter_colors[our_color], FIXED_COLOUR_PRIORITY)
 		update_icon()
 
-/obj/item/wirecutters/update_icon()
+/obj/item/wirecutters/update_overlays()
+	. = ..()
 	if(!random_color) //icon override
 		return
-	cut_overlays()
 	var/mutable_appearance/base_overlay = mutable_appearance(icon, "cutters_cutty_thingy")
 	base_overlay.appearance_flags = RESET_COLOR
-	add_overlay(base_overlay)
+	. += base_overlay
 
 /obj/item/wirecutters/attack(mob/living/carbon/C, mob/user)
 	if(istype(C) && C.handcuffed && istype(C.handcuffed, /obj/item/restraints/handcuffs/cable))