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

chrome/browser/flag_descriptions.h

 // Copyright 2017 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.
 
 #ifndef CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 #define CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 
 // Includes needed for macros allowing conditional compilation of some strings.
 #include "build/build_config.h"
 #include "build/buildflag.h"
@@ skipping 3100 matching lines @@
 
 // Description for the flag to enable wake on packets.
 extern const char kWakeOnPacketsDescription[];
 
 // Title of the flag used to enable quick unlock pin.
 extern const char kQuickUnlockPin[];
 
 // 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[];
 
 // Description of the flag used to enable quick unlock fingerprint.
 extern const char kQuickUnlockFingerprintDescription[];
 
 // Name of the about:flag option for experimental accessibility features.
 extern const char kExperimentalAccessibilityFeaturesName[];
 
 // Description of the about:flag option for experimental accessibility features.
@@ skipping 98 matching lines @@
 extern const char kEnableCopylessPasteName[];
 
 // Description of the flag that enables Copyless Paste.
 extern const char kEnableCopylessPasteDescription[];
 
 #endif  // defined(OS_ANDROID)
 
 }  // namespace flag_descriptions
 
 #endif  // CHROME_BROWSER_FLAG_DESCRIPTIONS_H_