To avoid the requirement of defining unnecessary gyp variables for

remoting/remoting_options.gypi

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'chromium_code': 1,
 
     # Set this to run the jscompile checks after building the webapp.
     'run_jscompile%': 0,
 
     # Set this to enable cast mode on the android client.
     'enable_cast%': 0,
 
     'variables': {
       'conditions': [
         # Enable the multi-process host on Windows by default.
         ['OS=="win"', {
           'remoting_multi_process%': 1,
         }, {
           'remoting_multi_process%': 0,
         }],
       ],
     },
     'remoting_multi_process%': '<(remoting_multi_process)',
 
     'remoting_rdp_session%': 1,
 
     'branding_path': '../remoting/branding_<(branding)',
+
+    # The ar_service_environment variable is used to define the target
+    # environment for the app being built.
+    # The allowed values are dev, test, staging, and prod.
+    'conditions': [
+      ['buildtype == "Dev"', {
+        'ar_service_environment%': 'dev',
+      }, {  # buildtype != 'Dev'
+        # Non-dev build must have this set to 'prod'.
+        'ar_service_environment': 'prod',
+      }],
+    ],  # conditions
+
   },
 }