Milo: Add task expired as a failure status

milo/appengine/swarming/build.go

Index: milo/appengine/swarming/build.go
diff --git a/milo/appengine/swarming/build.go b/milo/appengine/swarming/build.go
index afd1745f145a70d84d6db9685d48ea1466cd3795..6fec9443404f1aaa22abee6df128ff9102f2a8c1 100644
--- a/milo/appengine/swarming/build.go
+++ b/milo/appengine/swarming/build.go
@@ -282,17 +282,23 @@ func addTaskToMiloStep(c context.Context, server string, sr *swarming.SwarmingRp
 
 	case TaskExpired, TaskTimedOut, TaskBotDied:
 		step.Status = miloProto.Status_FAILURE
-		step.FailureDetails = &miloProto.FailureDetails{
-			Type: miloProto.FailureDetails_INFRA,
-		}
 
 		switch sr.State {
 		case TaskExpired:
-			step.FailureDetails.Text = "Task expired"
+			step.FailureDetails = &miloProto.FailureDetails{
+				Type: miloProto.FailureDetails_EXPIRED,
+				Text: "Task expired",
+			}
 		case TaskTimedOut:
-			step.FailureDetails.Text = "Task timed out"
+			step.FailureDetails = &miloProto.FailureDetails{
+				Type: miloProto.FailureDetails_INFRA,
+				Text: "Task timed out",
+			}
 		case TaskBotDied:
-			step.FailureDetails.Text = "Bot died"
+			step.FailureDetails = &miloProto.FailureDetails{
+				Type: miloProto.FailureDetails_INFRA,
+				Text: "Bot died",
+			}
 		}
 
 	case TaskCanceled: