Add track timer

osu.Game/Screens/Edit/Components/TimeInfoContainer.cs

@@ -1,9 +1,45 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using osu.Framework.Graphics;
+using osu.Game.Graphics.Sprites;
+using System;
+
 namespace osu.Game.Screens.Edit.Components
 {
     public class TimeInfoContainer : BottomBarContainer
     {
+        private const int count_duration = 150;
+
+        private readonly OsuSpriteText trackTimer;
+        private double savedTime;
+
+        public TimeInfoContainer()
+        {
+            Children = new Drawable[]
+            {
+                trackTimer = new OsuSpriteText
+                {
+                    Origin = Anchor.BottomLeft,
+                    RelativePositionAxes = Axes.Y,
+                    TextSize = 22,
+                    FixedWidth = true,
+                    Y = 0.5f,
+                }
+            };
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            var currentTime = Track.CurrentTime;
+
+            if (savedTime == currentTime)
+                return;
+
+            trackTimer.Text = TimeSpan.FromMilliseconds(currentTime).ToString(@"mm\:ss\:fff");
+            savedTime = currentTime;
+        }
     }
 }