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 52 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(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 280 matching lines @@
   // -- just before CreateProfile().
 
   // Initialize the screen locker now so that it can receive
   // LOGIN_USER_CHANGED notification from UserManager.
   if (chromeos::KioskModeHelper::IsKioskModeEnabled()) {
     chromeos::InitializeKioskModeIdleLogout();
   } else {
     chromeos::ScreenLocker::InitClass();
   }
 
+#if 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
+
   // This forces the ProfileManager to be created and register for the
   // notification it needs to track the logged in user.
   g_browser_process->profile_manager();
 
   // TODO(abarth): Should this move to InitializeNetworkOptions()?
   // Allow access to file:// on ChromeOS for tests.
   if (parsed_command_line().HasSwitch(switches::kAllowFileAccess))
     net::URLRequest::AllowFileAccess();
 
   // There are two use cases for kLoginUser:
@@ skipping 166 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();
 }