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 51b573d0db84428287c568d25fe123f47339e5ca..c166a5851845ced347015a2e142f754013ced697 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -941,6 +941,10 @@ const char kPinUnlockMinimumLength[] = "pin_unlock_minimum_length";
 const char kPinUnlockMaximumLength[] = "pin_unlock_maximum_length";
 // Boolean pref indicating whether users are allowed to set easy pins.
 const char kPinUnlockWeakPinsAllowed[] = "pin_unlock_weak_pins_allowed";
+
+// 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