Cache trait look-ups in the constructor where possible for Air activities/traits

OpenRA.Mods.Common/Activities/Air/FlyOffMap.cs

@@ -0,0 +1,35 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2015 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 OpenRA.Activities;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Activities
+{
+	public class FlyOffMap : Activity
+	{
+		readonly Plane plane;
+
+		public FlyOffMap(Actor self)
+		{
+			plane = self.Trait<Plane>();
+		}
+
+		public override Activity Tick(Actor self)
+		{
+			if (IsCanceled || !self.World.Map.Contains(self.Location))
+				return NextActivity;
+
+			Fly.FlyToward(self, plane, plane.Facing, plane.Info.CruiseAltitude);
+			return this;
+		}
+	}
+}