cros: Add PinStorageProvider enum which describes pin backend in use.

chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h

 // Copyright 2016 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_CHROMEOS_LOGIN_QUICK_UNLOCK_QUICK_UNLOCK_UTILS_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_QUICK_UNLOCK_QUICK_UNLOCK_UTILS_H_
 
 namespace base {
 class TimeDelta;
 }
@@ skipping 18 matching lines @@
 base::TimeDelta PasswordConfirmationFrequencyToTimeDelta(
     PasswordConfirmationFrequency frequency);
 
 // Register quick unlock prefs.
 void RegisterProfilePrefs(PrefRegistrySimple* registry);
 
 // Returns true if PIN unlock is allowed by policy and the quick unlock feature
 // flag is present.
 bool IsPinEnabled(PrefService* pref_service);
 
+// What subsystem should provide pin storage and authentication?
+enum class PinStorageType { kPrefs, kCryptohome };
+
+// Returns the pin storage type that should be used. IsPinEnabled() must
+// return true for this result to be valid.
+PinStorageType GetPinStorageType();
+
 // Returns true if the fingerprint unlock feature flag is present.
 bool IsFingerprintEnabled();
 
-// Forcibly enable quick-unlock for testing.
-void EnableForTesting();
+// Forcibly enable all quick-unlock modes for testing.
+void EnableForTesting(PinStorageType pin_storage_type);
 
 }  // namespace quick_unlock
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_QUICK_UNLOCK_QUICK_UNLOCK_UTILS_H_