Imported Upstream version 4.3.2.467

Former-commit-id: 9c2cb47f45fa221e661ab616387c9cda183f283d

mcs/class/System/System.Diagnostics/DefaultTraceListener.cs

@@ -160,11 +160,14 @@ namespace System.Diagnostics {
 		public override void Fail (string message, string detailMessage)
 		{
 			base.Fail (message, detailMessage);
+#if !MOBILE
 			if (ProcessUI (message, detailMessage) == DialogResult.Abort)
 				Thread.CurrentThread.Abort ();
+#endif
 			WriteLine (new StackTrace().ToString());
 		}
 
+#if !MOBILE
 		DialogResult ProcessUI (string message, string detailMessage)
 		{
 			
@@ -210,6 +213,7 @@ namespace System.Diagnostics {
 			Ignore,
 			Abort
 		}
+#endif
 
 		[MethodImplAttribute(MethodImplOptions.InternalCall)]
 		private extern static void WriteWindowsDebugString (string message);

mcs/class/System/System.Diagnostics/Stopwatch.cs

@@ -113,6 +113,8 @@ namespace System.Diagnostics
 			if (!is_running)
 				return;
 			elapsed += GetTimestamp () - started;
+			if (elapsed < 0)
+				elapsed = 0;
 			is_running = false;
 		}