Separate default beatmap skins from DefaultSkin

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -324,7 +324,7 @@ namespace osu.Game.Beatmaps
         public bool SkinLoaded => skin.IsResultAvailable;
         public ISkin Skin => skin.Value;
 
-        protected virtual ISkin GetSkin() => new DefaultSkin(null);
+        protected virtual ISkin GetSkin() => new BeatmapSkin(BeatmapInfo);
         private readonly RecyclableLazy<ISkin> skin;
 
         public abstract Stream GetStream(string storagePath);

osu.Game/Skinning/BeatmapSkin.cs

@@ -0,0 +1,32 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics.OpenGL.Textures;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Audio;
+using osu.Game.Beatmaps;
+
+namespace osu.Game.Skinning
+{
+    /// <summary>
+    /// An empty implementation of a beatmap skin, serves as a temporary default for <see cref="WorkingBeatmap"/>s.
+    /// </summary>
+    /// <remarks>
+    /// This should be removed once <see cref="Skin"/> becomes instantiable or a new skin type for osu!lazer beatmaps is defined.
+    /// </remarks>
+    public class BeatmapSkin : Skin
+    {
+        public BeatmapSkin(BeatmapInfo beatmap)
+            : base(BeatmapSkinExtensions.CreateSkinInfo(beatmap), null)
+        {
+        }
+
+        public override Texture GetTexture(string componentName, WrapMode wrapModeS, WrapMode wrapModeT) => null;
+
+        public override IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => null;
+
+        public override ISample GetSample(ISampleInfo sampleInfo) => null;
+    }
+}