Change IPC to make sense.

osu.Game/IPC/BeatmapIPCChannel.cs

@@ -0,0 +1,43 @@
+// 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.Diagnostics;
+using System.Threading.Tasks;
+using osu.Framework.Platform;
+using osu.Game.Database;
+
+namespace osu.Game.IPC
+{
+    public class BeatmapIPCChannel : IpcChannel<BeatmapImportMessage>
+    {
+        private BeatmapDatabase beatmaps;
+
+        public BeatmapIPCChannel(IIpcHost host, BeatmapDatabase beatmaps = null)
+            : base(host)
+        {
+            this.beatmaps = beatmaps;
+            MessageReceived += (msg) =>
+            {
+                Debug.Assert(beatmaps != null);
+                ImportAsync(msg.Path);
+            };
+        }
+
+        public async Task ImportAsync(string path)
+        {
+            if (beatmaps == null)
+            {
+                //we want to contact a remote osu! to handle the import.
+                await SendMessageAsync(new BeatmapImportMessage { Path = path });
+                return;
+            }
+
+            beatmaps.Import(path);
+        }
+    }
+
+    public class BeatmapImportMessage
+    {
+        public string Path;
+    }
+}