adopt pref value to enable/disable fingerprint authentication

Bug: 834424
Change-Id: I66544344b31a2fa37ca7ef58cefbc3ffd3beaac0
Reviewed-on: https://chromium-review.googlesource.com/1033797
Commit-Queue: Xiaoyin Hu <xiaoyinh@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554851}

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

@@ -23,7 +23,8 @@ FingerprintStorage::FingerprintStorage(PrefService* pref_service)
 FingerprintStorage::~FingerprintStorage() {}
 
 bool FingerprintStorage::IsFingerprintAuthenticationAvailable() const {
-  return !ExceededUnlockAttempts() && IsFingerprintEnabled() && HasRecord();
+  return !ExceededUnlockAttempts() && IsFingerprintEnabled() &&
+         AuthenticationEnabled() && HasRecord();
 }
 
 bool FingerprintStorage::HasRecord() const {
@@ -42,5 +43,9 @@ bool FingerprintStorage::ExceededUnlockAttempts() const {
   return unlock_attempt_count() >= kMaximumUnlockAttempts;
 }
 
+bool FingerprintStorage::AuthenticationEnabled() const {
+  return pref_service_->GetBoolean(prefs::kEnableQuickUnlockFingerprint);
+}
+
 }  // namespace quick_unlock
 }  // namespace chromeos

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

@@ -40,6 +40,9 @@ class FingerprintStorage {
   // Returns true if the user has exceeded fingerprint unlock attempts.
   bool ExceededUnlockAttempts() const;
 
+  // Returns true if user has enabled fingerprint to unlock device.
+  bool AuthenticationEnabled() const;
+
   int unlock_attempt_count() const { return unlock_attempt_count_; }
 
  private:

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

@@ -30,6 +30,11 @@ class FingerprintStorageUnitTest : public testing::Test {
                                      records_number);
   }
 
+  void SetAuthenticationPref(bool enabled) {
+    profile_->GetPrefs()->SetBoolean(prefs::kEnableQuickUnlockFingerprint,
+                                     enabled);
+  }
+
   content::TestBrowserThreadBundle thread_bundle_;
   std::unique_ptr<TestingProfile> profile_;
 
@@ -77,8 +82,9 @@ TEST_F(FingerprintStorageUnitTest, UnlockAttemptCount) {
 }
 
 // Verifies that authentication is not available when
-// 1. No fingerprint records registered
-// 2. Too many authentication attempts
+// 1. Authentication pref is disabled.
+// 2. No fingerprint records registered.
+// 3. Too many authentication attempts.
 TEST_F(FingerprintStorageUnitTest, AuthenticationUnAvailable) {
   quick_unlock::FingerprintStorage* fingerprint_storage =
       quick_unlock::QuickUnlockFactory::GetForProfile(profile_.get())
@@ -89,6 +95,10 @@ TEST_F(FingerprintStorageUnitTest, AuthenticationUnAvailable) {
   SetRecords(1);
   EXPECT_TRUE(fingerprint_storage->HasRecord());
   EXPECT_EQ(0, fingerprint_storage->unlock_attempt_count());
+
+  // Authentication pref is disabled by default.
+  EXPECT_FALSE(test_api.IsFingerprintAuthenticationAvailable());
+  SetAuthenticationPref(true /*enabled*/);
   EXPECT_TRUE(test_api.IsFingerprintAuthenticationAvailable());
 
   // No fingerprint records registered makes fingerprint authentication