[iOS][Password Check] Delay password check result

This change adds delay before revealing password check result. Delay is
added only if it took less than 3 seconds to finish the check.

Bug: 1075494
Change-Id: Ibc1031e870e178a98b1f74f4122c9519a8e15d28
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2351975Reviewed-by: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Ioana Pandele <ioanap@chromium.org>
Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Commit-Queue: Viktor Semeniuk <vsemeniuk@google.com>
Cr-Commit-Position: refs/heads/master@{#798601}

ios/chrome/browser/passwords/ios_chrome_password_check_manager.h

@@ -142,6 +142,10 @@ class IOSChromePasswordCheckManager
   // delegate is initialized.
   bool start_check_on_init_ = false;
 
+  // Time when password check was started. Used to calculate delay in case
+  // when password check run less than 3 seconds.
+  base::Time start_time_;
+
   // A scoped observer for |saved_passwords_presenter_|.
   ScopedObserver<password_manager::SavedPasswordsPresenter,
                  password_manager::SavedPasswordsPresenter::Observer>
@@ -159,6 +163,8 @@ class IOSChromePasswordCheckManager
 
   // Observers to listen to password check changes.
   base::ObserverList<Observer> observers_;
+
+  base::WeakPtrFactory<IOSChromePasswordCheckManager> weak_ptr_factory_{this};
 };
 
 #endif  // IOS_CHROME_BROWSER_PASSWORDS_IOS_CHROME_PASSWORD_CHECK_MANAGER_H_

ios/chrome/browser/passwords/ios_chrome_password_check_manager.mm

@@ -26,6 +26,8 @@ using State = password_manager::BulkLeakCheckServiceInterface::State;
 
 // Key used to attach UserData to a LeakCheckCredential.
 constexpr char kPasswordCheckDataKey[] = "password-check-manager-data-key";
+// Minimum time the check should be running.
+constexpr base::TimeDelta kDelay = base::TimeDelta::FromSeconds(3);
 
 // Class which ensures that IOSChromePasswordCheckManager will stay alive
 // until password check is completed even if class what initially created
@@ -120,6 +122,7 @@ void IOSChromePasswordCheckManager::StartPasswordCheck() {
     bulk_leak_check_service_adapter_.StartBulkLeakCheck(kPasswordCheckDataKey,
                                                         &data);
     is_check_running_ = true;
+    start_time_ = base::Time::Now();
   } else {
     start_check_on_init_ = true;
   }
@@ -207,6 +210,20 @@ void IOSChromePasswordCheckManager::OnStateChanged(State state) {
         base::Time::Now().ToDoubleT());
   }
   if (state != State::kRunning) {
+    // If check was running
+    if (is_check_running_) {
+      const base::TimeDelta elapsed = base::Time::Now() - start_time_;
+      if (elapsed < kDelay) {
+        base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
+            FROM_HERE,
+            base::BindOnce(&IOSChromePasswordCheckManager::
+                               NotifyPasswordCheckStatusChanged,
+                           weak_ptr_factory_.GetWeakPtr()),
+            kDelay - elapsed);
+        is_check_running_ = false;
+        return;
+      }
+    }
     is_check_running_ = false;
   }
   NotifyPasswordCheckStatusChanged();

ios/chrome/browser/passwords/ios_chrome_password_check_manager_unittest.mm

@@ -157,6 +157,8 @@ class IOSChromePasswordCheckManagerTest : public PlatformTest {
 
   void RunUntilIdle() { task_env_.RunUntilIdle(); }
 
+  void FastForwardBy(base::TimeDelta time) { task_env_.FastForwardBy(time); }
+
   ChromeBrowserState* browser_state() { return browser_state_.get(); }
   TestPasswordStore& store() { return *store_; }
   MockBulkLeakCheckService* service() { return bulk_leak_check_service_; }
@@ -389,3 +391,28 @@ TEST_F(IOSChromePasswordCheckManagerTest, EditCompromisedPassword) {
   EXPECT_EQ(base::UTF8ToUTF16(kPassword2),
             store().stored_passwords().at(kExampleCom).at(0).password_value);
 }
+
+// Tests expected delay is being added.
+TEST_F(IOSChromePasswordCheckManagerTest, CheckFinishedWithDelay) {
+  store().AddLogin(MakeSavedPassword(kExampleCom, kUsername1));
+
+  RunUntilIdle();
+  StrictMock<MockPasswordCheckManagerObserver> observer;
+  manager().AddObserver(&observer);
+  manager().StartPasswordCheck();
+  RunUntilIdle();
+
+  EXPECT_CALL(observer, PasswordCheckStatusChanged(PasswordCheckState::kIdle))
+      .Times(0);
+  static_cast<BulkLeakCheckServiceInterface::Observer*>(&manager())
+      ->OnStateChanged(BulkLeakCheckServiceInterface::State::kIdle);
+  FastForwardBy(base::TimeDelta::FromSeconds(1));
+
+  EXPECT_CALL(observer, PasswordCheckStatusChanged(PasswordCheckState::kIdle))
+      .Times(0);
+  FastForwardBy(base::TimeDelta::FromSeconds(1));
+
+  EXPECT_CALL(observer, PasswordCheckStatusChanged(PasswordCheckState::kIdle))
+      .Times(1);
+  FastForwardBy(base::TimeDelta::FromSeconds(1));
+}

ios/chrome/browser/passwords/password_check_observer_bridge.mm

@@ -20,7 +20,11 @@ PasswordCheckObserverBridge::~PasswordCheckObserverBridge() = default;
 
 void PasswordCheckObserverBridge::PasswordCheckStatusChanged(
     PasswordCheckState status) {
-  [delegate_ passwordCheckStateDidChange:status];
+  // Since password check state update can be called with delay from the
+  // background thread, dispatch aync should be used to update main UI thread.
+  dispatch_async(dispatch_get_main_queue(), ^{
+    [delegate_ passwordCheckStateDidChange:status];
+  });
 }
 
 void PasswordCheckObserverBridge::CompromisedCredentialsChanged(

ios/chrome/browser/ui/settings/password/passwords_table_view_controller.mm

@@ -1369,8 +1369,7 @@ std::vector<std::unique_ptr<autofill::PasswordForm>> CopyOf(
       }
       break;
     case ItemTypeCheckForProblemsButton:
-      if (_passwordCheck->GetPasswordCheckState() !=
-          PasswordCheckState::kNoPasswords) {
+      if (self.passwordCheckState != PasswordCheckStateRunning) {
         _passwordCheck->StartPasswordCheck();
       }
       break;