Add sync experiment flag for wallet datatype.

components/autofill/core/common/autofill_pref_names.cc

 // Copyright 2013 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/autofill/core/common/autofill_pref_names.h"
 
 namespace autofill {
 namespace prefs {
 
 // Boolean that is true when auxiliary Autofill profiles are enabled. This pref
@@ skipping 20 matching lines @@
 // Double that indicates negative (for not matched forms) upload rate.
 const char kAutofillNegativeUploadRate[] = "autofill.negative_upload_rate";
 
 // Double that indicates positive (for matched forms) upload rate.
 const char kAutofillPositiveUploadRate[] = "autofill.positive_upload_rate";
 
 // Whether Autofill should try to use the Mac Address Book. If this value is
 // true, then kAutofillMacAddressBookQueried is expected to also be true.
 const char kAutofillUseMacAddressBook[] = "autofill.use_mac_address_book";
 
-// Boolean that's true when Wallet card and address import is enabled.
+// Boolean that's true when Wallet card and address import is enabled by the
+// user. This will only be available to the user if the overall feature is
+// enabled.
 const char kAutofillWalletImportEnabled[] = "autofill.wallet_import_enabled";
 
+// Enables/disables the Wallet card and address feature. Set via sync
+// experiment. Even if this is false, the feature can still be enabled via the
+// command line flag flags::kEnableWalletCardImport.
+const char kAutofillWalletSyncExperimentEnabled[] =
+    "autofill.wallet_import_sync_experiment_enabled";
+
 }  // namespace prefs
 }  // namespace autofill