Adding Finch and flag for Sign-in promo

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";
 
+// Disables sign-in promo.
+const char kDisableSigninPromo[] = "disable-signin-promo";
+
 // Disables sending signin scoped device id to LSO with refresh token request.
 const char kDisableSigninScopedDeviceId[] = "disable-signin-scoped-device-id";
 
 // Enables consistent identity features.
 const char kEnableAccountConsistency[] = "enable-account-consistency";
 
 // Enables sending EnableRefreshTokenAnnotationRequest.
 extern const char kEnableRefreshTokenAnnotationRequest[] =
     "enable-refresh-token-annotation-request";
 
+// Enables sign-in promo.
+const char kEnableSigninPromo[] = "enable-signin-promo";
+
 // Enables multiple account versions of chrome.identity APIs.
 const char kExtensionsMultiAccount[] = "extensions-multi-account";
 
 // Enables or disables the new password separated sign in flow in a tab modal
 // dialog.
 const base::Feature kUsePasswordSeparatedSigninFlow {
   "UsePasswordSeparatedSigninFlow", base::FEATURE_ENABLED_BY_DEFAULT
 };
 
 }  // namespace switches