Save display preference when all display configuration changes has been completed.

chrome/browser/chromeos/display/display_configuration_observer.cc

Index: chrome/browser/chromeos/display/display_configuration_observer.cc
diff --git a/chrome/browser/chromeos/display/display_configuration_observer.cc b/chrome/browser/chromeos/display/display_configuration_observer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f9a2bdcd7c23c01a75da9e040c13ad19e4898dd7
--- /dev/null
+++ b/chrome/browser/chromeos/display/display_configuration_observer.cc
@@ -0,0 +1,28 @@
+// Copyright (c) 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 "chrome/browser/chromeos/display/display_configuration_observer.h"
+
+#include "ash/display/display_controller.h"
+#include "ash/shell.h"
+#include "chrome/browser/chromeos/display/display_preferences.h"
+
+namespace chromeos {
+
+DisplayConfigurationObserver::DisplayConfigurationObserver() {
+  ash::Shell::GetInstance()->display_controller()->AddObserver(this);
+}
+
+DisplayConfigurationObserver::~DisplayConfigurationObserver() {
+  ash::Shell::GetInstance()->display_controller()->RemoveObserver(this);
+}
+
+void DisplayConfigurationObserver::OnDisplayConfigurationChanging() {
+}
+
+void DisplayConfigurationObserver::OnDisplayConfigurationChanged() {
+  StoreDisplayPrefs();
+}
+
+}  // namespace chromeos