md-settings: Added settings for fingerprint unlock.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index e7c71f438e4fd227de75ebd2aa16220719594247..c69af21e402ff64cca9ccc00c268fb48d8de08cd 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -924,6 +924,10 @@ const char kQuickUnlockModeWhitelist[] = "quick_unlock_mode_whitelist";
 // 2 - day. Users will have to enter their password every day.
 // 3 - week. Users will have to enter their password every week.
 const char kQuickUnlockTimeout[] = "quick_unlock_timeout";
+
+// Boolean pref indicating whether fingerprint unlock is enabled.
+const char kEnableQuickUnlockFingerprint[] =
+    "settings.enable_quick_unlock_fingerprint";
 #endif  // defined(OS_CHROMEOS)
 
 // A boolean pref set to true if a Home button to open the Home pages should be