Revert of Disallow posting tasks to SequencedWorkerPools by default.

base/threading/sequenced_worker_pool_unittest.cc

Index: base/threading/sequenced_worker_pool_unittest.cc
diff --git a/base/threading/sequenced_worker_pool_unittest.cc b/base/threading/sequenced_worker_pool_unittest.cc
index 941436fda26f0fe26eccce2ca13ccfac1c363c24..5782af7e767b631bffcb0c3551895ea9a55a2d02 100644
--- a/base/threading/sequenced_worker_pool_unittest.cc
+++ b/base/threading/sequenced_worker_pool_unittest.cc
@@ -253,12 +253,8 @@
       TaskScheduler::CreateAndSetDefaultTaskScheduler(
           std::move(worker_pool_params),
           base::Bind([](const TaskTraits&) -> size_t { return 0U; }));
-
-      // 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();
+      SequencedWorkerPool::ResetRedirectToTaskSchedulerForProcessForTesting();
+      SequencedWorkerPool::RedirectToTaskSchedulerForProcess();
     }
   }
 
@@ -270,12 +266,7 @@
     DeletePool();
 
     if (RedirectedToTaskScheduler()) {
-      // Reset SequencedWorkerPool to its original state (i.e. enabled without
-      // redirection to TaskScheduler).
-      SequencedWorkerPool::DisableForProcessForTesting();
-      SequencedWorkerPool::EnableForProcess();
-
-      // Delete the registered TaskScheduler.
+      SequencedWorkerPool::ResetRedirectToTaskSchedulerForProcessForTesting();
       DeleteTaskScheduler();
     }
   }