TaskScheduler: Set the IO allowed bit in TaskTracker::RunTask().

base/task_scheduler/scheduler_worker_pool_impl.cc

Index: base/task_scheduler/scheduler_worker_pool_impl.cc
diff --git a/base/task_scheduler/scheduler_worker_pool_impl.cc b/base/task_scheduler/scheduler_worker_pool_impl.cc
index f2d69344f4cfb6da35f4932b6ad3aa4ba0d7d739..a0ba116c2ac2020b318e8bedf72052cd8d4eea6d 100644
--- a/base/task_scheduler/scheduler_worker_pool_impl.cc
+++ b/base/task_scheduler/scheduler_worker_pool_impl.cc
@@ -310,7 +310,6 @@ std::unique_ptr<SchedulerWorkerPoolImpl> SchedulerWorkerPoolImpl::Create(
     DelayedTaskManager* delayed_task_manager) {
   std::unique_ptr<SchedulerWorkerPoolImpl> worker_pool(
       new SchedulerWorkerPoolImpl(params.name(),
-                                  params.io_restriction(),
                                   params.suggested_reclaim_time(),
                                   task_tracker, delayed_task_manager));
   if (worker_pool->Initialize(
@@ -519,10 +518,6 @@ void SchedulerWorkerPoolImpl::SchedulerWorkerDelegateImpl::OnMainEntry(
 
   // New threads haven't run GetWork() yet, so reset the |idle_start_time_|.
   idle_start_time_ = TimeTicks();
-
-  ThreadRestrictions::SetIOAllowed(
-      outer_->io_restriction_ ==
-          SchedulerWorkerPoolParams::IORestriction::ALLOWED);
 }
 
 scoped_refptr<Sequence>
@@ -676,12 +671,10 @@ void SchedulerWorkerPoolImpl::SchedulerWorkerDelegateImpl::OnDetach() {
 
 SchedulerWorkerPoolImpl::SchedulerWorkerPoolImpl(
     StringPiece name,
-    SchedulerWorkerPoolParams::IORestriction io_restriction,
     const TimeDelta& suggested_reclaim_time,
     TaskTracker* task_tracker,
     DelayedTaskManager* delayed_task_manager)
     : name_(name.as_string()),
-      io_restriction_(io_restriction),
       suggested_reclaim_time_(suggested_reclaim_time),
       idle_workers_stack_lock_(shared_priority_queue_.container_lock()),
       idle_workers_stack_cv_for_testing_(