cros: Remove supervised user methods from SystemTrayDelegate

ash/system/tray/system_tray_delegate.cc

Index: ash/system/tray/system_tray_delegate.cc
diff --git a/ash/system/tray/system_tray_delegate.cc b/ash/system/tray/system_tray_delegate.cc
index 7868d10948541229af8d1b0bbfe535d361a313d5..5fc51d9109881de17df17e6255f5bbc4eb94c4db 100644
--- a/ash/system/tray/system_tray_delegate.cc
+++ b/ash/system/tray/system_tray_delegate.cc
@@ -31,18 +31,6 @@ base::string16 SystemTrayDelegate::GetEnterpriseMessage() const {
   return base::string16();
 }
 
-std::string SystemTrayDelegate::GetSupervisedUserManager() const {
-  return std::string();
-}
-
-base::string16 SystemTrayDelegate::GetSupervisedUserManagerName() const {
-  return base::string16();
-}
-
-base::string16 SystemTrayDelegate::GetSupervisedUserMessage() const {
-  return base::string16();
-}
-
 void SystemTrayDelegate::ShowEnterpriseInfo() {}
 
 void SystemTrayDelegate::ShowUserLogin() {}
@@ -82,12 +70,6 @@ bool SystemTrayDelegate::IsSearchKeyMappedToCapsLock() {
   return false;
 }
 
-void SystemTrayDelegate::AddCustodianInfoTrayObserver(
-    CustodianInfoTrayObserver* observer) {}
-
-void SystemTrayDelegate::RemoveCustodianInfoTrayObserver(
-    CustodianInfoTrayObserver* observer) {}
-
 std::unique_ptr<SystemTrayItem> SystemTrayDelegate::CreateRotationLockTrayItem(
     SystemTray* tray) {
   return nullptr;