Remove participants, add match chat

osu.Game/Screens/Multi/Match/Components/MatchChatDisplay.cs

@@ -0,0 +1,30 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Game.Online.Chat;
+using osu.Game.Online.Multiplayer;
+
+namespace osu.Game.Screens.Multi.Match.Components
+{
+    public class MatchChatDisplay : StandAloneChatDisplay
+    {
+        private readonly Room room;
+
+        [Resolved]
+        private ChannelManager channelManager { get; set; }
+
+        public MatchChatDisplay(Room room)
+            : base(true)
+        {
+            this.room = room;
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            Channel.Value = channelManager.JoinChannel(new Channel { Id = room.ChannelId, Type = ChannelType.Multiplayer, Name = $"#mp_{room.RoomID}" });
+        }
+    }
+}