Use task_scheduler in c/b/chromeos/arc/process/arc_process_service.cc

BUG=chromium:667892
TEST=try, start ARC, press Search+ESC to show the UI

Change-Id: I96b9cefaddbe26dc78edcb5217cae58d3c4a6a81
Reviewed-on: https://chromium-review.googlesource.com/580012Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Yusuke Sato <yusukes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488569}

chrome/browser/chromeos/arc/process/arc_process_service.cc

@@ -22,7 +22,8 @@
 #include "base/process/process.h"
 #include "base/process/process_iterator.h"
 #include "base/task_runner_util.h"
-#include "base/threading/sequenced_worker_pool.h"
+#include "base/task_scheduler/post_task.h"
+#include "base/task_scheduler/task_traits.h"
 #include "base/trace_event/trace_event.h"
 #include "components/arc/arc_bridge_service.h"
 #include "components/arc/arc_browser_context_keyed_service_factory_base.h"
@@ -233,10 +234,9 @@ ArcProcessService::ArcProcessService(content::BrowserContext* context,
       nspid_to_pid_(new NSPidToPidMap()),
       weak_ptr_factory_(this) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  auto* blocking_pool = content::BrowserThread::GetBlockingPool();
-  task_runner_ = blocking_pool->GetSequencedTaskRunnerWithShutdownBehavior(
-      blocking_pool->GetSequenceToken(),
-      base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+  task_runner_ = base::CreateSequencedTaskRunnerWithTraits(
+      {base::MayBlock(), base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN,
+       base::TaskPriority::USER_VISIBLE});
   arc_bridge_service_->process()->AddObserver(this);
 }