Adding Finch and flag for Sign-in promo

components/signin/core/common/signin_switches.cc

Index: components/signin/core/common/signin_switches.cc
diff --git a/components/signin/core/common/signin_switches.cc b/components/signin/core/common/signin_switches.cc
index 3fdb3a9859d3016e75165b00139535b2e143926f..393a10dbf8b3e7efff392c4593de0a5167517f68 100644
--- a/components/signin/core/common/signin_switches.cc
+++ b/components/signin/core/common/signin_switches.cc
@@ -16,6 +16,9 @@ const char kDisableAccountConsistency[] = "disable-account-consistency";
 // Disables new profile management system, including new profile chooser UI.
 const char kDisableNewProfileManagement[] = "disable-new-profile-management";
 
+// 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";
 
@@ -29,6 +32,9 @@ const char kEnableNewProfileManagement[] = "new-profile-management";
 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";