Save display preference on boot

chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc

Index: chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc b/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
index 8fdfe73cb06a79dec29a53a80b3ca4e5d4f23218..39a7887846891d479784a8a15b88bbc003408e26 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate_chromeos.cc
@@ -15,6 +15,7 @@
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/chromeos/accessibility/magnification_manager.h"
 #include "chrome/browser/chromeos/background/ash_user_wallpaper_delegate.h"
+#include "chrome/browser/chromeos/display/display_configuration_observer.h"
 #include "chrome/browser/chromeos/display/display_preferences.h"
 #include "chrome/browser/chromeos/extensions/media_player_api.h"
 #include "chrome/browser/chromeos/extensions/media_player_event_router.h"
@@ -207,12 +208,18 @@ bool ChromeShellDelegate::IsFirstRunAfterBoot() const {
 
 void ChromeShellDelegate::PreInit() {
   chromeos::LoadDisplayPreferences(IsFirstRunAfterBoot());
+  display_configuration_observer_.reset(
+      new chromeos::DisplayConfigurationObserver());

[Jun Mukai, 2014/01/13 23:51:15]

I'm not sure why moving display_configuration_observer_ to ShellDelegate. 
What's the point? Could you describe why on the CL description or a comment?

[oshima, 2014/01/13 23:58:19]

This should happen before Shell::Init so that observer can store the initial
state. I updated the description and added comment.

 }
 
 void ChromeShellDelegate::Shutdown() {
   content::RecordAction(content::UserMetricsAction("Shutdown"));
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       RequestShutdown();
+
+  // Let classes unregister themselves as observers of the ash::Shell singleton
+  // before the shell is destroyed.
+  display_configuration_observer_.reset();
 }
 
 ash::CapsLockDelegate* ChromeShellDelegate::CreateCapsLockDelegate() {