Refactor Flammable to be ECS. (#4671)

- Refactor IHotItem into IsHotEvent.
- Refactor IFireAct into TileFireEvent.

Content.Server/Tools/Components/WelderComponent.cs

@@ -33,9 +33,8 @@ namespace Content.Server.Tools.Components
     [RegisterComponent]
     [ComponentReference(typeof(ToolComponent))]
     [ComponentReference(typeof(IToolComponent))]
-    [ComponentReference(typeof(IHotItem))]
     [NetworkedComponent()]
-    public class WelderComponent : ToolComponent, IUse, ISuicideAct, IHotItem, IAfterInteract
+    public class WelderComponent : ToolComponent, IUse, ISuicideAct, IAfterInteract
     {
         [Dependency] private readonly IEntitySystemManager _entitySystemManager = default!;
 
@@ -98,11 +97,6 @@ namespace Content.Server.Tools.Components
             }
         }
 
-        bool IHotItem.IsCurrentlyHot()
-        {
-            return WelderLit;
-        }
-
         protected override void Initialize()
         {
             base.Initialize();

Content.Server/Tools/WelderSystem.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using Content.Server.Tools.Components;
 using Content.Shared.Chemistry.EntitySystems;
 using Content.Shared.Examine;
+using Content.Shared.Temperature;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Localization;
 
@@ -21,9 +22,15 @@ namespace Content.Server.Tools
             base.Initialize();
 
             SubscribeLocalEvent<WelderComponent, SolutionChangedEvent>(OnSolutionChange);
+            SubscribeLocalEvent<WelderComponent, IsHotEvent>(OnIsHotEvent);
             SubscribeLocalEvent<WelderComponent, ExaminedEvent>(OnExamine);
         }
 
+        private void OnIsHotEvent(EntityUid uid, WelderComponent component, IsHotEvent args)
+        {
+            args.IsHot = component.WelderLit;
+        }
+
         private void OnExamine(EntityUid uid, WelderComponent component, ExaminedEvent args)
         {
             if (component.WelderLit)