Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

mcs/class/corlib/System.Threading/HostExecutionContext.cs

@@ -29,7 +29,7 @@
 namespace System.Threading {
 
 	[MonoTODO ("Useless until the runtime supports it")]
-	public class HostExecutionContext {
+	public class HostExecutionContext : IDisposable {
 
 		private object _state;
 
@@ -52,5 +52,15 @@ namespace System.Threading {
 			get { return _state; }
 			set { _state = value; }
 		}
+
+		public void Dispose ()
+		{
+			Dispose (true);
+			GC.SuppressFinalize (this);
+		}
+
+		public virtual void Dispose (bool disposing)
+		{
+		}
 	}
 }