Refactoring to SongProgress in osu.Game.Screens.Play, moving out progress bar into it's own class

osu.Game/Screens/Play/SongProgressGraph.cs

@@ -0,0 +1,84 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using OpenTK;
+using System;
+using System.Collections.Generic;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Primitives;
+using osu.Framework.Graphics;
+
+namespace osu.Game.Screens.Play
+{
+    public class SongProgressGraph : BufferedContainer
+    {
+        private List<SongProgressGraphColumn> columns = new List<SongProgressGraphColumn>();
+        private float lastDrawWidth;
+
+        public override bool HandleInput => false;
+        public int ColumnCount => columns.Count;
+
+        private int progress;
+        public int Progress
+        {
+            get
+            {
+                return progress;
+            }
+            set
+            {
+                if (value == progress) return;
+                progress = value;
+
+                redrawProgress();
+            }
+        }
+
+        private void redrawProgress()
+        {
+            for (int i = 0; i < columns.Count; i++)
+            {
+                columns[i].State = i <= progress ? ColumnState.Lit : ColumnState.Dimmed;
+            }
+
+            ForceRedraw();
+        }
+
+        private void recreateGraph()
+        {
+            RemoveAll(delegate { return true; }, true);
+            columns.RemoveAll(delegate { return true; });
+
+            // Random filled values used for testing for now
+            var random = new Random();
+            for (int column = 0; column < DrawWidth; column += 3)
+            {
+                columns.Add(new SongProgressGraphColumn
+                {
+                    Position = new Vector2(column + 1, 0),
+                    Filled = random.Next(1, 11),
+                    State = ColumnState.Dimmed
+                });
+
+                Add(columns[columns.Count - 1]);
+            }
+
+            redrawProgress();
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            if (DrawWidth == lastDrawWidth) return;
+            //recreateGraph();
+            lastDrawWidth = DrawWidth;
+        }
+
+        public SongProgressGraph()
+        {
+            CacheDrawnFrameBuffer = true;
+            PixelSnapping = true;
+        }
+    }
+}