Imported Upstream version 3.10.0

Former-commit-id: 172c8e3c300b39d5785c7a3e8dfb08ebdbc1a99b

mcs/tools/mdoc/Mono.Documentation/preserver.cs

@@ -0,0 +1,34 @@
+// Command to preserve member documentation for types that are changing in a subsequent version
+// By Joel Martinez <joel.martinez@xamarin.com
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Mono.Options;
+
+namespace Mono.Documentation
+{
+	public class MDocPreserve : MDocCommand
+	{
+		MDocUpdater updater;
+
+		public MDocPreserve ()
+		{
+			updater = new MDocUpdater ();
+		}
+
+		public override void Run (IEnumerable<string> args)
+		{
+			string preserveName = string.Empty;
+			var p = new OptionSet () { { "name=",
+					"Root {DIRECTORY} to generate/update documentation.",
+					v => preserveName = v
+				}
+			};
+
+			updater.PreserveTag = preserveName;
+
+			updater.Run (args);
+		}
+	}
+}
+