Asynchronously load wallpapers when user pod is selected.

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.cc
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
index dfb30fa445c4d609791fa71fc9f8d04f3869ba5c..5f110c317268d546c457e5b65c323e11a3a6f77f 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
@@ -14,7 +14,6 @@
 #include "base/string_split.h"
 #include "chrome/browser/browser_process_impl.h"
 #include "chrome/browser/chromeos/audio/audio_handler.h"
-#include "chrome/browser/chromeos/background/desktop_background_observer.h"
 #include "chrome/browser/chromeos/boot_times_loader.h"
 #include "chrome/browser/chromeos/cros/cros_library.h"
 #include "chrome/browser/chromeos/cryptohome/async_method_caller.h"
@@ -361,10 +360,6 @@ void ChromeBrowserMainPartsChromeos::PreProfileInit() {
 
   // In Aura builds this will initialize ash::Shell.
   ChromeBrowserMainPartsLinux::PreProfileInit();
-
-  // Initialize desktop background observer so that it can receive
-  // LOGIN_USER_CHANGED notification from UserManager.
-  desktop_background_observer_.reset(new chromeos::DesktopBackgroundObserver);
 }
 
 void ChromeBrowserMainPartsChromeos::PostProfileInit() {