Merge all pooling support into Playfield

osu.Game/Rulesets/UI/IPooledHitObjectProvider.cs

@@ -0,0 +1,20 @@
+// 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 JetBrains.Annotations;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Drawables;
+
+namespace osu.Game.Rulesets.UI
+{
+    internal interface IPooledHitObjectProvider
+    {
+        /// <summary>
+        /// Attempts to retrieve the poolable <see cref="DrawableHitObject"/> representation of a <see cref="HitObject"/>.
+        /// </summary>
+        /// <param name="hitObject">The <see cref="HitObject"/> to retrieve the <see cref="DrawableHitObject"/> representation of.</param>
+        /// <returns>The <see cref="DrawableHitObject"/> representing <see cref="HitObject"/>, or <c>null</c> if no poolable representation exists.</returns>
+        [CanBeNull]
+        public DrawableHitObject GetPooledDrawableRepresentation([NotNull] HitObject hitObject);
+    }
+}