chromeos: Remove SystemTrayDelegate::GetIMEManagedMessage()

ash/system/tray/system_tray_delegate.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 "ash/system/tray/system_tray_delegate.h"
 
 #include "ash/system/tray/ime_info.h"
 
 namespace ash {
 
 SystemTrayDelegate::SystemTrayDelegate() = default;
 
 SystemTrayDelegate::~SystemTrayDelegate() = default;
 
 void SystemTrayDelegate::Initialize() {}
 
 void SystemTrayDelegate::ShowUserLogin() {}
 
 void SystemTrayDelegate::GetCurrentIME(IMEInfo* info) {}
 
 void SystemTrayDelegate::GetAvailableIMEList(IMEInfoList* list) {}
 
 void SystemTrayDelegate::GetCurrentIMEProperties(IMEPropertyInfoList* list) {}
 
-base::string16 SystemTrayDelegate::GetIMEManagedMessage() {
-  return base::string16();
-}
-
 NetworkingConfigDelegate* SystemTrayDelegate::GetNetworkingConfigDelegate()
     const {
   return nullptr;
 }
 
 bool SystemTrayDelegate::GetSessionStartTime(
     base::TimeTicks* session_start_time) {
   return false;
 }
 
 bool SystemTrayDelegate::GetSessionLengthLimit(
     base::TimeDelta* session_length_limit) {
   return false;
 }
 
 void SystemTrayDelegate::ActiveUserWasChanged() {}
 
 bool SystemTrayDelegate::IsSearchKeyMappedToCapsLock() {
   return false;
 }
 
 }  // namespace ash