Add LogicKeyListenerWidget for binding keys to UI logic.

OpenRA.Mods.RA/Widgets/LogicKeyListenerWidget.cs

@@ -0,0 +1,25 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using OpenRA.Widgets;
+
+namespace OpenRA.Mods.RA.Widgets
+{
+	public class LogicKeyListenerWidget : Widget
+	{
+		public Func<KeyInput, bool> OnKeyPress = _ => false;
+
+		public override bool HandleKeyPress(KeyInput e)
+		{
+			return OnKeyPress(e);
+		}
+	}
+}