Milo: Add task expired as a failure status

common/proto/milo/annotations.proto

 // Copyright (c) 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 syntax = "proto3";
 
 package milo;
 
 import "google/protobuf/timestamp.proto";
 
@@ skipping 13 matching lines @@
 message FailureDetails {
   // Type is the type of failure.
   enum Type {
     // The failure is a general failure.
     GENERAL = 0;
     // An unhandled exception occured during execution.
     EXCEPTION = 1;
     // The failure is related to a failed infrastructure component, not an error
     // with the Step itself.
     INFRA = 2;
+    // The failure was due to an resource exhausion. The step was scheduled
+    // but never ran, and never will run.
+    EXPIRED = 3;

[dnj, 2016/09/06 16:46:52]

NO, bad! This protobuf is already in play, and you cannot bump constant values.
Add this at the end after CANCELLED.

[hinoka, 2016/09/07 22:13:58]

Done.

     // The failure is due to a failed Dungeon Master dependency. This should be
     // used if a Step's external depdendency fails and the Step cannot recover
     // or proceed without it.
-    DM_DEPENDENCY_FAILED = 3;
+    DM_DEPENDENCY_FAILED = 4;
     // The step was cancelled.
-    CANCELLED = 4;
+    CANCELLED = 5;
   }
   Type type = 1;
 
   // An optional string describing the failure.
   string text = 2;
 
   // If the failure type is DEPENDENCY_FAILED, the failed dependencies should be
   // listed here.
   repeated DMLink failed_dm_dependency = 3;
 }
@@ skipping 136 matching lines @@
 
   // The quest name.
   string quest = 2;
 
   // The attempt number.
   int64 attempt = 3;
 
   // The execution number.
   int64 execution = 4;
 }