Cleanups in remoting gn files.

remoting/remoting_options.gni

 # 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/chrome_build.gni")
+import("//build/config/ui.gni")
+
+enable_remoting_host =
+    is_win || (is_linux && (is_chromeos || use_x11)) || is_mac
+enable_me2me_host = is_win || (is_linux && !is_chromeos && use_x11) || is_mac
 
 # These arguments can be overridden from the command line (see "gn help args").
 declare_args() {
   # Set this to run the jscompile checks after building the webapp.
   enable_remoting_jscompile = false
 
   # Set this to enable building internal AppRemoting apps.
   enable_internal_app_remoting_targets = false
 }
 
@@ skipping 20 matching lines @@
 # The allowed values are dev and prod.
 if (is_debug) {
   ar_service_environment = "dev"
 } else {
   # Non-dev builds should default to 'prod'.
   ar_service_environment = "prod"
 }
 
 daemon_controller_guid = "655bd819-c08c-4b04-80c2-f160739ff6ef"
 rdp_desktop_session_guid = "6a7699f0-ee43-43e7-aa30-a6738f9bd470"