Create class hierarchy for Score/Replay storage.

osu.Game/Input/Handlers/ReplayInputHandler.cs

@@ -0,0 +1,41 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using osu.Framework.Input.Handlers;
+using osu.Framework.MathUtils;
+using osu.Framework.Platform;
+using OpenTK;
+using osu.Framework.Input;
+using osu.Game.IO.Legacy;
+using OpenTK.Input;
+using KeyboardState = osu.Framework.Input.KeyboardState;
+using MouseState = osu.Framework.Input.MouseState;
+
+namespace osu.Game.Input.Handlers
+{
+    public abstract class ReplayInputHandler : InputHandler
+    {
+        /// <summary>
+        /// A function provided to convert replay coordinates from gamefield to screen space.
+        /// </summary>
+        public Func<Vector2, Vector2> ToScreenSpace { protected get; set; }
+
+        /// <summary>
+        /// Update the current frame based on an incoming time value.
+        /// There are cases where we return a "must-use" time value that is different from the input.
+        /// This is to ensure accurate playback of replay data.
+        /// </summary>
+        /// <param name="time">The time which we should use for finding the current frame.</param>
+        /// <returns>The usable time value. If null, we shouldn't be running components reliant on this data.</returns>
+        public abstract double? SetFrameFromTime(double time);
+
+        public override bool Initialize(GameHost host) => true;
+
+        public override bool IsActive => true;
+
+        public override int Priority => 0;
+    }
+}