Adds support for multiple displays to WmTestBase

ash/mus/BUILD.gn

 # Copyright 2015 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")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//services/shell/public/cpp/service.gni")
 import("//services/shell/public/service_manifest.gni")
 import("//tools/grit/repack.gni")
 
@@ skipping 178 matching lines @@
     "accelerators/accelerator_registrar_unittest.cc",
     "app_launch_unittest.cc",
     "bridge/wm_shell_mus_test_api.h",
     "bridge/wm_window_mus_test_api.h",
     "layout_manager_unittest.cc",
     "root_window_controller_unittest.cc",
     "test/wm_test_base.cc",
     "test/wm_test_base.h",
     "test/wm_test_helper.cc",
     "test/wm_test_helper.h",
-    "test/wm_test_screen.cc",
-    "test/wm_test_screen.h",
     "window_manager_unittest.cc",
     "wm/container_finder_unittest.cc",
     "wm/mru_window_tracker_unittest.cc",
     "workspace/workspace_layout_manager_unittest.cc",
   ]
 
   deps = [
     ":lib",
     ":resources",
     "//ash",
@@ skipping 24 matching lines @@
     "//ui/views/mus",
   ]
 
   data_deps = [
     ":mus",
     "//mash/quick_launch",
   ]
 
   defines = [ "NOTIMPLEMENTED_POLICY=5" ]
 }