chromeos: Don't explicitly set system tray visibility during initialization

ash/common/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/common/system/tray/system_tray_delegate.h"
 
 #include "ash/common/system/tray/ime_info.h"
 #include "ash/common/system/tray/system_tray_item.h"
 
 namespace ash {
@@ skipping 17 matching lines @@
       factory_reset_required(false) {}
 
 UpdateInfo::~UpdateInfo() {}
 
 SystemTrayDelegate::SystemTrayDelegate() {}
 
 SystemTrayDelegate::~SystemTrayDelegate() {}
 
 void SystemTrayDelegate::Initialize() {}
 
-bool SystemTrayDelegate::GetTrayVisibilityOnStartup() {
-  return false;
-}
-
 LoginStatus SystemTrayDelegate::GetUserLoginStatus() const {
   return LoginStatus::NOT_LOGGED_IN;
 }
 
 std::string SystemTrayDelegate::GetEnterpriseDomain() const {
   return std::string();
 }
 
 base::string16 SystemTrayDelegate::GetEnterpriseMessage() const {
   return base::string16();
@@ skipping 142 matching lines @@
 VPNDelegate* SystemTrayDelegate::GetVPNDelegate() const {
   return nullptr;
 }
 
 std::unique_ptr<SystemTrayItem> SystemTrayDelegate::CreateRotationLockTrayItem(
     SystemTray* tray) {
   return nullptr;
 }
 
 }  // namespace ash