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

chrome/test/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/common/features.gni")
@@ skipping 2070 matching lines @@
         "../browser/ui/ash/accelerator_controller_browsertest.cc",
         "../browser/ui/ash/app_list/app_list_controller_ash_browsertest.cc",
         "../browser/ui/ash/chrome_new_window_client_browsertest.cc",
         "../browser/ui/ash/keyboard_controller_browsertest.cc",
         "../browser/ui/ash/launcher/chrome_launcher_controller_impl_browsertest.cc",
         "../browser/ui/ash/launcher/launcher_favicon_loader_browsertest.cc",
         "../browser/ui/ash/multi_user/multi_user_window_manager_test.cc",
         "../browser/ui/ash/multi_user/multi_user_window_manager_test.h",
         "../browser/ui/ash/networking_config_delegate_chromeos_browsertest.cc",
         "../browser/ui/ash/shelf_browsertest.cc",
+        "../browser/ui/ash/system_tray_client_browsertest.cc",
         "../browser/ui/ash/system_tray_delegate_chromeos_browsertest_chromeos.cc",
         "../browser/ui/ash/system_tray_tray_cast_browsertest_media_router_chromeos.cc",
         "../browser/ui/ash/volume_controller_browsertest.cc",
         "../browser/ui/views/frame/browser_non_client_frame_view_ash_browsertest.cc",
       ]
       deps += [
         "//ash/test:ash_with_aura_test_support",
         "//ash/test:test_support_with_content",
       ]
 
@@ skipping 3017 matching lines @@
 }
 
 if (is_win) {
   loadable_module("conflicts_dll") {
     testonly = true
     sources = [
       "conflicts/conflicts_dll.cc",
     ]
   }
 }