Add developer shortcut to reload chrome files

Hitting Ctrl+Shift+C will re-initialize the chrome provider,
reloading all chrome files instantly. Useful when changing the
UI.

Note: A new "RootWidget" was created to trap top-level (global)
shortcuts instead of putting everything in Widget.

OpenRA.Game/Widgets/RootWidget.cs

@@ -0,0 +1,39 @@
+#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.Graphics;
+
+namespace OpenRA.Widgets
+{
+	public class RootWidget : ContainerWidget
+	{
+		public RootWidget()
+		{
+			IgnoreMouseOver = true;
+		}
+
+		public override bool HandleKeyPress(KeyInput e)
+		{
+			if (e.Event == KeyInputEvent.Down)
+			{
+				var hk = Hotkey.FromKeyInput(e);
+
+				if (hk == Game.Settings.Keys.DevReloadChromeKey)
+				{
+					ChromeProvider.Initialize();
+					return true;
+				}
+			}
+
+			return base.HandleKeyPress(e);
+		}
+	}
+}

OpenRA.Game/Widgets/Widget.cs

@@ -19,7 +19,7 @@ namespace OpenRA.Widgets
 {
 	public static class Ui
 	{
-		public static Widget Root = new ContainerWidget();
+		public static Widget Root = new RootWidget();
 
 		public static int LastTickTime = Environment.TickCount;