Add a command-line flag for overriding variations country.

components/variations/variations_switches.cc

 // 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.
 
 #include "components/variations/variations_switches.h"
 
 namespace variations {
 namespace switches {
 
 // Disable field trial tests configured in fieldtrial_testing_config.json.
 const char kDisableFieldTrialTestingConfig[] = "disable-field-trial-config";
 
 // Fakes the channel of the browser for purposes of Variations filtering. This
 // is to be used for testing only. Possible values are "stable", "beta", "dev"
 // and "canary". Note that this only applies if the browser's reported channel
 // is UNKNOWN.
 const char kFakeVariationsChannel[] = "fake-variations-channel";
 
 // This option can be used to force parameters of field trials when testing
 // changes locally. The argument is a param list of (key, value) pairs prefixed
 // by an associated (trial, group) pair. You specify the param list for multiple
 // (trial, group) pairs with a comma separator.
 // Example:
 //   "Trial1.Group1:k1/v1/k2/v2,Trial2.Group2:k3/v3/k4/v4"
 // Trial names, groups names, parameter names, and value should all be URL
 // escaped for all non-alphanumeric characters.
 const char kForceFieldTrialParams[] = "force-fieldtrial-params";
 
+// Allows overriding the country used for evaluating variations. This is similar
+// to the "Override Variations Country" entry on chrome://translate-internals,
+// but is exposed as a command-line flag to allow testing First Run scenarios.
+// Additionally, unlike chrome://translate-internals, the value isn't persisted
+// across sessions.
+const char kVariationsOverrideCountry[] = "variations-override-country";
+
 // Specifies a custom URL for the server which reports variation data to the
 // client. Specifying this switch enables the Variations service on
 // unofficial builds. See variations_service.cc.
 const char kVariationsServerURL[] = "variations-server-url";
 
 }  // namespace switches
 }  // namespace variations