Add support for virtual displays

ui/display/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")
 import("//testing/test.gni")
 
 if (is_chromeos) {
   component("display") {
     sources = [
       "chromeos/apply_content_protection_task.cc",
       "chromeos/apply_content_protection_task.h",
       "chromeos/configure_displays_task.cc",
       "chromeos/configure_displays_task.h",
       "chromeos/display_configurator.cc",
       "chromeos/display_configurator.h",
       "chromeos/display_layout_manager.h",
+      "chromeos/display_snapshot_virtual.cc",
+      "chromeos/display_snapshot_virtual.h",
       "chromeos/display_util.cc",
       "chromeos/display_util.h",
       "chromeos/ozone/display_configurator_ozone.cc",
       "chromeos/query_content_protection_task.cc",
       "chromeos/query_content_protection_task.h",
       "chromeos/update_display_configuration_task.cc",
       "chromeos/update_display_configuration_task.h",
       "chromeos/x11/display_configurator_x11.cc",
       "chromeos/x11/display_mode_x11.cc",
       "chromeos/x11/display_mode_x11.h",
@@ skipping 87 matching lines @@
       "chromeos/test/test_native_display_delegate.h",
     ]
 
     public_deps = [
       ":display",
     ]
     deps = [
       "//base",
       "//ui/display/types",
       "//ui/gfx",
+      "//ui/gfx:test_support",
       "//ui/gfx/geometry",
     ]
   }
 }
 
 # TODO(GYP): Delete this after we've converted everything to GN.
 # The _run targets exist only for compatibility w/ GYP.
 group("display_unittests_run") {
   testonly = true
   deps = [
@@ skipping 34 matching lines @@
     ]
   }
 
   if (use_ozone && is_chromeos) {
     sources -= [
       "chromeos/x11/display_util_x11_unittest.cc",
       "chromeos/x11/native_display_event_dispatcher_x11_unittest.cc",
     ]
   }
 }