[Launcher per display] Removed Shell::status_area_widget(), system_tray()
 HasPrimaryStatusArea/GetPrimarySystemTray for login screen
 which will have only one tray/status area on primary

BUG=145978
TEST=none

Review URL: https://chromiumcodereview.appspot.com/11476033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@172169 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ash/extended_desktop_unittest.cc b/ash/extended_desktop_unittest.cc
index c153a601..716b9f26 100644
--- a/ash/extended_desktop_unittest.cc
+++ b/ash/extended_desktop_unittest.cc
@@ -577,7 +577,7 @@
 
 TEST_F(ExtendedDesktopTest, OpenSystemTray) {
   UpdateDisplay("500x600,600x400");
-  SystemTray* tray = ash::Shell::GetInstance()->system_tray();
+  SystemTray* tray = ash::Shell::GetInstance()->GetPrimarySystemTray();
   ASSERT_FALSE(tray->HasSystemBubble());
 
   // Opens the tray by a dummy click event and makes sure that adding/removing