Wait for display configuration to finish before suspending

ash/system/chromeos/power/power_event_observer.cc

 // Copyright 2013 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 "ash/system/chromeos/power/power_event_observer.h"
 
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray_notifier.h"
 #include "ash/wm/power_button_controller.h"
@@ skipping 19 matching lines @@
   }
 }
 
 // Tells the compositor for each of the displays to resume sending rendering
 // requests to the GPU.
 void ResumeRenderingRequests() {
   for (aura::Window* window : Shell::GetAllRootWindows())
     window->GetHost()->compositor()->SetVisible(true);
 }
 
+void OnSuspendDisplaysCompleted(const base::Closure& suspend_callback,
+                                bool status) {
+  suspend_callback.Run();
+}
+
 }  // namespace
 
 PowerEventObserver::PowerEventObserver()
     : screen_locked_(false), waiting_for_lock_screen_animations_(false) {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       AddObserver(this);
   chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->
       AddObserver(this);
 }
 
@@ skipping 56 matching lines @@
     screen_lock_callback_ = chromeos::DBusThreadManager::Get()
                                 ->GetPowerManagerClient()
                                 ->GetSuspendReadinessCallback();
   } else {
     // The lock-before-suspending pref is not set or the screen has already been
     // locked and the animations have completed.  Rendering can be stopped now.
     StopRenderingRequests();
   }
 
   ui::UserActivityDetector::Get()->OnDisplayPowerChanging();
-  shell->display_configurator()->SuspendDisplays();
+  shell->display_configurator()->SuspendDisplays(base::Bind(
+      &OnSuspendDisplaysCompleted, chromeos::DBusThreadManager::Get()
+                                       ->GetPowerManagerClient()
+                                       ->GetSuspendReadinessCallback()));
 }
 
 void PowerEventObserver::SuspendDone(const base::TimeDelta& sleep_duration) {
   Shell::GetInstance()->display_configurator()->ResumeDisplays();
   Shell::GetInstance()->system_tray_notifier()->NotifyRefreshClock();
 
   // If the suspend request was being blocked while waiting for the lock
   // animation to complete, clear the blocker since the suspend has already
   // completed.  This prevents rendering requests from being blocked after a
   // resume if the lock screen took too long to show.
@@ skipping 13 matching lines @@
   } else {
     VLOG(1) << "Screen locked without suspend";
   }
 }
 
 void PowerEventObserver::ScreenIsUnlocked() {
   screen_locked_ = false;
 }
 
 }  // namespace ash