cros: Add flag to enable pin on sign-in screen.

chrome/browser/flag_descriptions.h

Index: chrome/browser/flag_descriptions.h
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 577f9290f3ba6ad6c7485870c3c9b763f29d7ea7..18c470aed539864e3411c5d858e7f25e338a0ec9 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -3147,12 +3147,18 @@ extern const char kWakeOnPacketsName[];
 // Description for the flag to enable wake on packets.
 extern const char kWakeOnPacketsDescription[];
 
-// Title of the flag used to enable quick unlock pin.
+// Title of the flag used to enable quick unlock PIN.
 extern const char kQuickUnlockPin[];
 
-// Description of the flag used to enable quick unlock pin.
+// Description of the flag used to enable quick unlock PIN.
 extern const char kQuickUnlockPinDescription[];
 
+// Title of the flag used to enable PIN on signin.
+extern const char kQuickUnlockPinSignin[];
+
+// Description of the flag used to enable PIN on signin.
+extern const char kQuickUnlockPinSigninDescription[];
+
 // Title of the flag used to enable quick unlock fingerprint.
 extern const char kQuickUnlockFingerprint[];