Make mojo/services pass in "gn check"

mojo/services/public/cpp/view_manager/tests/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/ui.gni")
 
 # GYP version: mojo/mojo_services.gypi:mojo_view_manager_lib_unittests
 test("mojo_view_manager_lib_unittests") {
   sources = [
     "view_unittest.cc",
     "view_manager_unittest.cc",
   ]
 
   deps = [
     "//base",
     "//base/test:test_support",
     "//testing/gtest",
     "//ui/gfx",
     "//ui/gfx:test_support",
+    "//mojo/application_manager",
     "//mojo/environment:chromium",
     "//mojo/services/public/interfaces/geometry",
     "//mojo/services/public/cpp/geometry",
     "//mojo/shell:test_support",
     "//mojo/services/public/interfaces/view_manager",
     "//mojo/services/public/cpp/view_manager",
   ]
   if (use_aura) {
     deps += [ "//mojo/services/public/cpp/view_manager/lib:run_unittests" ]
   } else {
     deps += [ "//mojo/common/test:run_all_unittests" ]
   }
 }