Add new flag for consistent identity.

components/signin/core/common/signin_switches.cc

 // 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.
 
 #include "components/signin/core/common/signin_switches.h"
 
 namespace switches {
 
 // Clears the token service before using it. This allows simulating the
 // expiration of credentials during testing.
 const char kClearTokenService[] = "clear-token-service";
 
+// Enables consistent identity features.
+const char kEnableAccountConsistency[] = "enable-account-consistency";
+
 // Enables the pure web-based flow for sign in on first run/NTP/wrench menu/
 // settings page.
 const char kEnableWebBasedSignin[] = "enable-web-based-signin";
 
 // Enables multiple account versions of chrome.identity APIs.
 const char kExtensionsMultiAccount[] = "extensions-multi-account";
 
 // Allows displaying the list of existing profiles in the avatar bubble for
 // fast switching between profiles.
 const char kFastUserSwitching[] = "fast-user-switching";
 
 // Enables using GAIA information to populate profile name and icon.
 const char kGoogleProfileInfo[] = "google-profile-info";
 
 // Use new avatar menu. When combined with new-profile-management, it simply
 // shows the new profile management avatar menu. Otherwise it shows a redesigned
 // avatar menu with the same functionality as the old one, plus a tutorial card
 // at the top prompting the user to try out the new profile management UI.
 const char kNewAvatarMenu[] = "new-avatar-menu";
 
 // Use new profile management system, including profile sign-out and new
 // choosers.
 const char kNewProfileManagement[] = "new-profile-management";
 
 }  // namespace switches