Change SchedulerWorker::ShouldExit Checks Ordering

base/task_scheduler/scheduler_worker.cc

 // Copyright 2016 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.
 
 #include "base/task_scheduler/scheduler_worker.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 313 matching lines @@
 void SchedulerWorker::CreateThread() {
   thread_ = Thread::Create(make_scoped_refptr(this));
 }
 
 void SchedulerWorker::CreateThreadAssertSynchronized() {
   thread_lock_.AssertAcquired();
   CreateThread();
 }
 
 bool SchedulerWorker::ShouldExit() {
-  return task_tracker_->IsShutdownComplete() ||
-         join_called_for_testing_.IsSet() || should_exit_.IsSet();
+  // The ordering of the checks is important below. This SchedulerWorker may be
+  // released and outlive |task_tracker_| in unit tests. However, when the
+  // SchedulerWorker is released, |should_exit_| will be set, so check that
+  // first.
+  return should_exit_.IsSet() || join_called_for_testing_.IsSet() ||
+         task_tracker_->IsShutdownComplete();
 }
 
 }  // namespace internal
 }  // namespace base