Use new StringID function.

appengine/cmd/cron/engine/engine.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Package engine implements the core logic of the cron service.
 package engine
 
 import (
         "bytes"
         "encoding/json"
@@ skipping 197 matching lines @@
         q := datastore.NewQuery("CronJob").Eq("Enabled", true)
         keys := []*datastore.Key{}
         if err := ds.GetAll(q, &keys); err != nil {
                 return errors.WrapTransient(err)
         }
         wg := sync.WaitGroup{}
         errs := errors.NewLazyMultiError(len(keys))
         for i, key := range keys {
                 wg.Add(1)
                 go func(i int, key *datastore.Key) {
-                        errs.Assign(i, e.resetJob(c, key.Last().StringID))
+                        errs.Assign(i, e.resetJob(c, key.StringID()))
                         wg.Done()
                 }(i, key)
         }
         wg.Wait()
         return errors.WrapTransient(errs.Get())
 }
 
 // getProjectJobs fetches from datastore all enabled jobs belonging to a given
 // project.
 func (e *engineImpl) getProjectJobs(c context.Context, projectID string) (map[string]*jobEntity, error) {
@@ skipping 327 matching lines @@
                 return cb(c, jobID, invocationID)
         }
         return e.txn(c, jobID, func(c context.Context, job *jobEntity, isNew bool) error {
                 if isNew {
                         logging.Errorf(c, "Running job is unexpectedly gone")
                         return errSkipPut
                 }
                 return e.rollSM(c, job, func(sm *StateMachine) error { return sm.OnInvocationDone(invocationID) })
         })
 }