ash: Use system tray mojo interface to show system update tray icon

ash/common/system/tray/default_system_tray_delegate.cc

 // Copyright 2013 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/common/system/tray/default_system_tray_delegate.h"
 
 #include <string>
-#include <utility>
-
-#include "ash/common/system/networking_config_delegate.h"
-#include "base/message_loop/message_loop.h"
-#include "base/time/time.h"
 
 namespace ash {
 
 DefaultSystemTrayDelegate::DefaultSystemTrayDelegate()
     : bluetooth_enabled_(true) {}
 
 DefaultSystemTrayDelegate::~DefaultSystemTrayDelegate() {}
 
 LoginStatus DefaultSystemTrayDelegate::GetUserLoginStatus() const {
   return LoginStatus::USER;
 }
 
 std::string DefaultSystemTrayDelegate::GetSupervisedUserManager() const {
   if (!IsUserSupervised())
     return std::string();
   return "manager@chrome.com";
 }
 
 bool DefaultSystemTrayDelegate::IsUserSupervised() const {
   return GetUserLoginStatus() == LoginStatus::SUPERVISED;
 }
 
-void DefaultSystemTrayDelegate::GetSystemUpdateInfo(UpdateInfo* info) const {
-  DCHECK(info);
-  info->severity = UpdateInfo::UPDATE_NONE;
-  info->update_required = true;
-  info->factory_reset_required = false;
-}
-
 bool DefaultSystemTrayDelegate::ShouldShowSettings() const {
   return true;
 }
 
 bool DefaultSystemTrayDelegate::ShouldShowNotificationTray() const {
   return true;
 }
 
 void DefaultSystemTrayDelegate::ToggleBluetooth() {
   bluetooth_enabled_ = !bluetooth_enabled_;
@@ skipping 14 matching lines @@
 bool DefaultSystemTrayDelegate::GetBluetoothDiscovering() {
   return false;
 }
 
 int DefaultSystemTrayDelegate::GetSystemTrayMenuWidth() {
   // This is the default width for English languages.
   return 300;
 }
 
 }  // namespace ash