IChromeButton support & RA rules change for it

OpenRa.Game/Traits/Chrome/PowerDownButton.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Linq;
+using OpenRa.Orders;
+
+namespace OpenRa.Traits
+{
+	class PowerDownButtonInfo : StatelessTraitInfo<PowerDownButton> { }
+
+	class PowerDownButton : IChromeButton
+	{
+		public string Image { get { return "repair"; } }	// todo: art
+		public bool Enabled { get { return true; } }
+		public bool Pressed { get { return Game.controller.orderGenerator is PowerDownOrderGenerator; } }
+		public void OnClick() { Game.controller.ToggleInputMode<PowerDownOrderGenerator>(); }
+	}
+
+	class SellButtonInfo : StatelessTraitInfo<SellButton> { }
+
+	class SellButton : IChromeButton
+	{
+		public string Image { get { return "sell"; } }
+		public bool Enabled { get { return true; } }
+		public bool Pressed { get { return Game.controller.orderGenerator is SellOrderGenerator; } }
+		public void OnClick() { Game.controller.ToggleInputMode<SellOrderGenerator>(); }
+	}
+
+	class RepairButtonInfo : StatelessTraitInfo<RepairButton> { }
+
+	class RepairButton : IChromeButton
+	{
+		public string Image { get { return "repair"; } }	// todo: art
+		public bool Enabled
+		{
+			get
+			{
+				if (!Game.Settings.RepairRequiresConyard)
+					return true;
+
+				return Game.world.Queries.OwnedBy[Game.world.LocalPlayer]
+					.WithTrait<ConstructionYard>().Any();
+			}
+		}
+
+		public bool Pressed { get { return Game.controller.orderGenerator is RepairOrderGenerator; } }
+		public void OnClick() { Game.controller.ToggleInputMode<RepairOrderGenerator>(); }
+	}
+}