Speed up ARC boot if the user launches ARC app while ARC is not ready

chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.cc

 // Copyright 2016 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 "chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.h"
 
 #include "chrome/browser/chromeos/arc/arc_support_host.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/app_list/arc/arc_app_utils.h"
 #include "chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_item_controller.h"
@@ skipping 196 matching lines @@
                                   ash::STATUS_RUNNING);
   } else {
     owner_->SetItemController(shelf_id, controller);
     owner_->SetItemStatus(shelf_id, ash::STATUS_RUNNING);
   }
 
   if (app_controller_map_.empty())
     RegisterNextUpdate();
 
   app_controller_map_[shelf_app_id] = controller;
+
+  // On some boards, ARC is booted with a restricted set of resources by default
+  // to avoid slowing down Chrome's user session restoration. However, the
+  // restriction should be lifted once the user explicitly tries to launch an
+  // ARC app.
+  arc::PrioritizeArcInstance();

[khmel, 2016/09/08 23:35:27]

nit: Probably it is better to put this into arc_app_utils into LaunchApp. This
would make logic more clear. App app launches pass through arc_app_utils. In
this case you may leave this file untouched and remove declaration from
arc_app_utils.h

[Yusuke Sato, 2016/09/09 16:20:12]

That's simpler, thanks. Done.

 }