cros: Added a new function to quick unlock api for checking unfinished pins.

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

 // 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.
 
 #include "chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.h"
 
 #include "base/feature_list.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
 #include "chrome/common/chrome_features.h"
@@ skipping 12 matching lines @@
 }  // namespace
 
 void RegisterQuickUnlockProfilePrefs(PrefRegistrySimple* registry) {
   base::ListValue quick_unlock_whitelist_default;
   quick_unlock_whitelist_default.AppendString(kQuickUnlockWhitelistOptionPin);
   registry->RegisterListPref(prefs::kQuickUnlockModeWhitelist,
                              quick_unlock_whitelist_default.DeepCopy());
   registry->RegisterIntegerPref(
       prefs::kQuickUnlockTimeout,
       static_cast<int>(QuickUnlockPasswordConfirmationFrequency::DAY));
+
+  // Preferences related the lock screen pin unlock.
+  registry->RegisterIntegerPref(prefs::kPinUnlockMinimumLength, 4);
+  // 0 indicates no maximum length for the pin.
+  registry->RegisterIntegerPref(prefs::kPinUnlockMaximumLength, 0);
+  registry->RegisterBooleanPref(prefs::kPinUnlockWeakPinsAllowed, true);
 }
 
 bool IsPinUnlockEnabled(PrefService* pref_service) {
   if (enable_for_testing_)
     return true;
 
   // Check if policy allows PIN.
   const base::ListValue* quick_unlock_whitelist =
       pref_service->GetList(prefs::kQuickUnlockModeWhitelist);
   base::StringValue all_value(kQuickUnlockWhitelistOptionAll);
@@ skipping 13 matching lines @@
 
   // Enable quick unlock only if the switch is present.
   return base::FeatureList::IsEnabled(features::kQuickUnlockPin);
 }
 
 void EnableQuickUnlockForTesting() {
   enable_for_testing_ = true;
 }
 
 }  // namespace chromeos