Enable user change background image in settings page in Aura build.

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

 // Copyright (c) 2012 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/chrome_browser_main_chromeos.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
@@ skipping 51 matching lines @@
 #include "content/public/common/main_function_params.h"
 #include "grit/platform_locale_settings.h"
 #include "net/base/network_change_notifier.h"
 #include "net/url_request/url_request.h"
 #include "ui/base/l10n/l10n_util.h"
 
 #if defined(TOOLKIT_USES_GTK)
 #include <gtk/gtk.h>
 #endif
 
+#if !defined(OS_WIN) && defined(USE_ASH)
+#include "chrome/browser/chromeos/background/desktop_background_observer.h"
+#endif
+
 #if defined(USE_AURA)
 #include "chrome/browser/chromeos/legacy_window_manager/initial_browser_window_observer.h"
 #include "chrome/browser/chromeos/power/power_button_controller_delegate_chromeos.h"
 #include "chrome/browser/chromeos/power/power_button_observer.h"
 #include "chrome/browser/chromeos/power/video_property_writer.h"
 #endif
 
 class MessageLoopObserver : public MessageLoopForUI::Observer {
 #if defined(USE_AURA)
   virtual base::EventStatus WillProcessEvent(
@@ skipping 320 matching lines @@
         content::NotificationService::AllSources(),
         content::NotificationService::NoDetails());
   } else if (parsed_command_line().HasSwitch(switches::kLoginManager)) {
     // Initialize status area mode early on.
     chromeos::StatusAreaViewChromeos::
         SetScreenMode(chromeos::StatusAreaViewChromeos::LOGIN_MODE_WEBUI);
   }
 
   // In Aura builds this will initialize ash::Shell.
   ChromeBrowserMainPartsLinux::PreProfileInit();
+
+#if !defined(OS_WIN) && defined(USE_ASH)
+  // Initialize desktop background observer so that it can receive
+  // LOGIN_USER_CHANGED notification from UserManager.
+  desktop_background_observer_.reset(new chromeos::DesktopBackgroundObserver);
+#endif
 }
 
 void ChromeBrowserMainPartsChromeos::PostProfileInit() {
   // -- This used to be in ChromeBrowserMainParts::PreMainMessageLoopRun()
   // -- just after CreateProfile().
 
   if (parsed_command_line().HasSwitch(switches::kLoginUser) &&
       !parsed_command_line().HasSwitch(switches::kLoginPassword)) {
     // Pass the TokenService pointer to the policy connector so user policy can
     // grab a token and register with the policy server.
@@ skipping 111 matching lines @@
   // Let VideoPropertyWriter unregister itself as an observer of the ash::Shell
   // singleton before the shell is destroyed.
   video_property_writer_.reset();
   // Remove PowerButtonObserver attached to a D-Bus client before
   // DBusThreadManager is shut down.
   power_button_observer_.reset();
 #endif
 
   ChromeBrowserMainPartsLinux::PostMainMessageLoopRun();
 }