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

chrome/browser/ui/app_list/arc/arc_app_utils.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/app_list/arc/arc_app_utils.h"
 
+#include <memory>
 #include <string>
 
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/synchronization/waitable_event.h"
 #include "chrome/browser/ui/app_list/arc/arc_app_list_prefs.h"
 #include "chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.h"
 #include "chrome/browser/ui/ash/launcher/chrome_launcher_controller.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+#include "chromeos/dbus/session_manager_client.h"
 #include "components/arc/arc_bridge_service.h"
 #include "ui/aura/window.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 
 namespace arc {
 
 namespace {
 
 // Default sizes to use.
@@ skipping 42 matching lines @@
   int bridge_version = bridge_service->app()->version();
   if (bridge_version < required_version) {
     VLOG(2) << "Request to " << service_name << " when Arc version "
             << bridge_version << " does not support it.";
     return nullptr;
   }
 
   return app_instance;
 }
 
+void PrioritizeArcInstanceCallback(bool success) {
+  VLOG(2) << "Finished prioritizing the instance: result=" << success;
+  if (!success)
+    LOG(ERROR) << "Failed to prioritize ARC";
+}
+
 // Find a proper size and position for a given rectangle on the screen.
 // TODO(skuhne): This needs more consideration, but it is lacking
 // WindowPositioner functionality since we do not have an Aura::Window yet.
 gfx::Rect GetTargetRect(const gfx::Size& size) {
   // Make sure that the window will fit into our workspace.
   // Note that Arc++ will always be on the primary screen (for now).
   // Note that Android's coordinate system is only valid inside the working
   // area. We can therefore ignore the provided left / top offsets.
   aura::Window* root = ash::Shell::GetPrimaryRootWindow();
   gfx::Rect work_area =
@@ skipping 283 matching lines @@
       GetAppInstance(kShowPackageInfoOnPageMinVersion, kShowPackageInfoStr);
   if (!app_instance)
     return false;
 
   app_instance->ShowPackageInfoOnPage(
       package_name, page,
       GetTargetRect(gfx::Size(kNexus7Width, kNexus7Height)));
   return true;
 }
 
+void PrioritizeArcInstance() {
+  VLOG(2) << "Prioritizing the instance";
+  chromeos::SessionManagerClient* session_manager_client =
+      chromeos::DBusThreadManager::Get()->GetSessionManagerClient();
+  session_manager_client->PrioritizeArcInstance(
+      base::Bind(PrioritizeArcInstanceCallback));
+}
+
 }  // namespace arc