Remove deprecated priority-less SequencedWorkerPool constructor.

chrome/browser/chromeos/arc/arc_process_service.cc

Index: chrome/browser/chromeos/arc/arc_process_service.cc
diff --git a/chrome/browser/chromeos/arc/arc_process_service.cc b/chrome/browser/chromeos/arc/arc_process_service.cc
index 78a203c3ef96ff2c98bb847985a5e8c06e68666b..a072efe831323de7ef5e0645d71c7803a2e2d57a 100644
--- a/chrome/browser/chromeos/arc/arc_process_service.cc
+++ b/chrome/browser/chromeos/arc/arc_process_service.cc
@@ -40,7 +40,9 @@ using std::vector;
 
 ArcProcessService::ArcProcessService(ArcBridgeService* bridge_service)
     : ArcService(bridge_service),
-      worker_pool_(new SequencedWorkerPool(1, "arc_process_manager")),
+      worker_pool_(new SequencedWorkerPool(1,
+                                           "arc_process_manager",
+                                           base::TaskPriority::USER_BLOCKING)),

[hidehiko, 2016/08/09 05:59:36]

This is ok for me, or can be USER_VISIBLE, to be consistent with the original
code.
There may be a room to lower the priority in a future CL.

Added cylee@ and nya@ for FYI.

[cylee1, 2016/08/09 08:35:41]

USER_VISIBLe looks good to me.

BTW there's an ongoing CL which changes SequencedWorkerPool to Thread. 
https://codereview.chromium.org/2025593003/
So this change is also temporarily.

[gab, 2016/08/09 14:24:06]

Done.

       weak_ptr_factory_(this) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   arc_bridge_service()->process()->AddObserver(this);