aura: Uber tray should not show up on start screen in kiosk mode.

chrome/browser/chromeos/system/ash_system_tray_delegate.cc

Index: chrome/browser/chromeos/system/ash_system_tray_delegate.cc
diff --git a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
index 093993ee37f2fe0560a93e8a3123c0c845f92537..6dd39fb36c19ce21a0f798e4d30a1803d9791dda 100644
--- a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
+++ b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
@@ -33,6 +33,7 @@
 #include "chrome/browser/chromeos/input_method/input_method_util.h"
 #include "chrome/browser/chromeos/input_method/input_method_whitelist.h"
 #include "chrome/browser/chromeos/input_method/xkeyboard.h"
+#include "chrome/browser/chromeos/kiosk_mode/kiosk_mode_settings.h"
 #include "chrome/browser/chromeos/login/base_login_display_host.h"
 #include "chrome/browser/chromeos/login/login_display_host.h"
 #include "chrome/browser/chromeos/login/user.h"
@@ -152,6 +153,10 @@ class SystemTrayDelegate : public ash::SystemTrayDelegate,
   }
 
   // Overridden from ash::SystemTrayDelegate:
+  virtual bool GetTrayVisibilityOnStartup() OVERRIDE {
+    return !chromeos::KioskModeSettings::Get()->IsKioskModeEnabled();
+  }
+
   virtual const std::string GetUserDisplayName() const OVERRIDE {
     return UserManager::Get()->GetLoggedInUser().GetDisplayName();
   }