Extract interface for solo statistics watcher

osu.Game/Online/Solo/ISoloStatisticsWatcher.cs

@@ -0,0 +1,23 @@
+// 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 System;
+using osu.Framework.Allocation;
+using osu.Game.Scoring;
+
+namespace osu.Game.Online.Solo
+{
+    /// <summary>
+    /// A component that delivers updates to the logged in user's gameplay statistics after completed scores.
+    /// </summary>
+    [Cached]
+    public interface ISoloStatisticsWatcher
+    {
+        /// <summary>
+        /// Registers for a user statistics update after the given <paramref name="score"/> has been processed server-side.
+        /// </summary>
+        /// <param name="score">The score to listen for the statistics update for.</param>
+        /// <param name="onUpdateReady">The callback to be invoked once the statistics update has been prepared.</param>
+        void RegisterForStatisticsUpdateAfter(ScoreInfo score, Action<SoloStatisticsUpdate> onUpdateReady);
+    }
+}

osu.Game/Online/Solo/SoloStatisticsWatcher.cs

@@ -20,7 +20,7 @@ namespace osu.Game.Online.Solo
     /// <summary>
     /// A persistent component that binds to the spectator server and API in order to deliver updates about the logged in user's gameplay statistics.
     /// </summary>
-    public partial class SoloStatisticsWatcher : Component
+    public partial class SoloStatisticsWatcher : Component, ISoloStatisticsWatcher
     {
         [Resolved]
         private SpectatorClient spectatorClient { get; set; } = null!;