[reference - do not submit] Always create four pools in TaskSchedulerImpl.

base/threading/sequenced_worker_pool_unittest.cc

 // Copyright (c) 2012 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/threading/sequenced_worker_pool.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <memory>
@@ skipping 226 matching lines @@
 
 class SequencedWorkerPoolTest
     : public testing::TestWithParam<SequencedWorkerPoolRedirection> {
  public:
   SequencedWorkerPoolTest()
       : pool_owner_(new SequencedWorkerPoolOwner(kNumWorkerThreads, "test")),
         tracker_(new TestTracker) {}
 
   void SetUp() override {
     if (RedirectedToTaskScheduler()) {
-      std::vector<SchedulerWorkerPoolParams> worker_pool_params;
-      worker_pool_params.emplace_back(
-          "SchedulerWorkerPoolName", ThreadPriority::NORMAL,
+      const SchedulerWorkerPoolParams worker_pool_params(
           SchedulerWorkerPoolParams::StandbyThreadPolicy::LAZY,
-          kNumWorkerThreads, TimeDelta::Max());
+          static_cast<int>(kNumWorkerThreads), TimeDelta::Max());
       TaskScheduler::CreateAndSetDefaultTaskScheduler(
-          std::move(worker_pool_params),
-          base::Bind([](const TaskTraits&) -> size_t { return 0U; }));
+          "SequencedWorkerPoolTest", {worker_pool_params, worker_pool_params,
+                                      worker_pool_params, worker_pool_params});
 
       // Unit tests run in an environment where SequencedWorkerPool is enabled
       // without redirection to TaskScheduler. For the current unit test,
       // disable it and re-enable it with redirection to TaskScheduler.
       SequencedWorkerPool::DisableForProcessForTesting();
       SequencedWorkerPool::EnableWithRedirectionToTaskSchedulerForProcess();
     }
   }
 
   void TearDown() override {
@@ skipping 973 matching lines @@
     SequencedWorkerPoolSequencedTaskRunner, SequencedTaskRunnerTest,
     SequencedWorkerPoolSequencedTaskRunnerTestDelegate);
 INSTANTIATE_TYPED_TEST_CASE_P(
     SequencedWorkerPoolSequencedTaskRunner,
     SequencedTaskRunnerDelayedTest,
     SequencedWorkerPoolSequencedTaskRunnerTestDelegate);
 
 }  // namespace
 
 }  // namespace base