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

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

Index: chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h
diff --git a/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h b/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h
index 8508fe469e882614532f3b1ea71591f5f3f8e9ff..9a2f6c706b347f82c8397602e77197b97dee8635 100644
--- a/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h
+++ b/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h
@@ -36,11 +36,18 @@ void RegisterProfilePrefs(PrefRegistrySimple* registry);
 // 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