md-settings: Added settings for fingerprint unlock.

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

Index: chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.cc
diff --git a/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.cc b/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.cc
index 3beae8927a1fa80f5b903877df4f881b2266fdd4..a2284e1f55cd1ff790a5bf565cb5c4e229fc1969 100644
--- a/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.cc
+++ b/chrome/browser/chromeos/login/quick_unlock/quick_unlock_utils.cc
@@ -9,6 +9,7 @@
 #include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
 #include "chrome/common/chrome_features.h"
 #include "chrome/common/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/user_manager/user_manager.h"
@@ -30,6 +31,9 @@ void RegisterQuickUnlockProfilePrefs(PrefRegistrySimple* registry) {
   registry->RegisterIntegerPref(
       prefs::kQuickUnlockTimeout,
       static_cast<int>(QuickUnlockPasswordConfirmationFrequency::DAY));
+  registry->RegisterBooleanPref(
+      prefs::kEnableQuickUnlockFingerprint, false,

[jdufault, 2016/12/01 17:11:19]

I believe the pref is syncable by default, so this flag is not needed (also drop
the include).

[sammiequon, 2016/12/01 20:52:28]

Done.

+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
 }
 
 bool IsPinUnlockEnabled(PrefService* pref_service) {
@@ -58,6 +62,14 @@ bool IsPinUnlockEnabled(PrefService* pref_service) {
   return base::FeatureList::IsEnabled(features::kQuickUnlockPin);
 }
 
+bool IsFingerprintUnlockEnabled() {
+  // Enable fingerprint unlock only if the switch is present. For now,
+  // fingerprint unlock will not be seen if quick unlock switch is not present,
+  // so check that too.
+  return base::FeatureList::IsEnabled(features::kQuickUnlockPin) &&

[jdufault, 2016/12/01 17:11:19]

Why are these tied together like this?

[sammiequon, 2016/12/01 20:52:29]

The fingerprint settings are under the lock screen so we cannot set it up
without kQuickUnlockPin enabled so it is not usuable with kQuickUnlockPin turned
off.

[jdufault, 2016/12/02 23:02:11]

You should update the comment with that info.

[sammiequon, 2016/12/03 21:40:51]

Done.

+         base::FeatureList::IsEnabled(features::kQuickUnlockFingerprint);
+}
+
 void EnableQuickUnlockForTesting() {
   enable_for_testing_ = true;
 }