[PwdCheckAndroid] Add logic to create and destroy PasswordCheckBridge

The PasswordCheckBridge needs to signal its C++ counterpart when it's no
longer needed in order to free up memory. Since the C++ bridge gets
destructed, we need to destroy the entire PasswordCheck component, so
that we don't end up with a partially initialized object.

The object responsible for the tear-down is the last object to need the
component. Possible cases are:

MainSettings > PasswordSettings > PasswordCheck -> MainSettings should call destroy
PasswordSettings > PasswordCheck -> PasswordSettings should call destroy
MainSettings > SafetyCheck > PasswordCheck -> MainSettings should call destroy
PasswordCheck (launched from the leak dialog) -> PasswordCheck should call destroy


Bug:1102025, 1101256

Change-Id: I6706ab489049da2192ccb8c03632cc5a7fe38609
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2297504
Commit-Queue: Ioana Pandele <ioanap@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Reviewed-by: Friedrich [CET] <fhorschig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792276}

chrome/android/BUILD.gn

@@ -972,7 +972,7 @@ android_library("chrome_test_java") {
     "//chrome/browser/image_fetcher:java",
     "//chrome/browser/offline_pages/android:java",
     "//chrome/browser/paint_preview/android:java",
-    "//chrome/browser/password_check/android:public_java",
+    "//chrome/browser/password_check:public_java",
     "//chrome/browser/password_manager/android_test_helpers:test_support_java",
     "//chrome/browser/performance_hints/android:java",
     "//chrome/browser/preferences:java",

chrome/android/java/src/org/chromium/chrome/browser/password_manager/PasswordCheckupLauncher.java

@@ -11,6 +11,7 @@ import org.chromium.chrome.browser.AppHooks;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.flags.ChromeFeatureList;
 import org.chromium.chrome.browser.password_check.PasswordCheckFactory;
+import org.chromium.chrome.browser.password_check.PasswordCheckReferrer;
 import org.chromium.ui.base.WindowAndroid;
 
 /**
@@ -31,7 +32,8 @@ public class PasswordCheckupLauncher {
     private static void launchLocalCheckup(WindowAndroid windowAndroid) {
         assert ChromeFeatureList.isEnabled(ChromeFeatureList.PASSWORD_CHECK);
         if (windowAndroid.getContext().get() == null) return; // Window not available yet/anymore.
-        PasswordCheckFactory.create().showUi(windowAndroid.getContext().get());
+        PasswordCheckFactory.getOrCreate().showUi(
+                windowAndroid.getContext().get(), PasswordCheckReferrer.LEAK_DIALOG);
     }
 
     private static boolean tryLaunchingNativePasswordCheckup(ChromeActivity activity) {

chrome/android/java/src/org/chromium/chrome/browser/password_manager/PasswordManagerLauncher.java

@@ -5,6 +5,7 @@
 package org.chromium.chrome.browser.password_manager;
 
 import android.app.Activity;
+import android.os.Bundle;
 
 import com.google.android.gms.common.ConnectionResult;
 
@@ -30,6 +31,11 @@ import java.lang.ref.WeakReference;
  * Bridge between Java and native PasswordManager code.
  */
 public class PasswordManagerLauncher {
+    // Key for the argument with which PasswordsSettings will be launched. The value for
+    // this argument should be part of the ManagePasswordsReferrer enum, which contains
+    // all points of entry to the passwords settings.
+    public static final String MANAGE_PASSWORDS_REFERRER = "manage-passwords-referrer";
+
     private static final String GOOGLE_ACCOUNT_PWM_UI = "google-password-manager";
 
     // Name of the parameter for the google-password-manager feature, used to override the default
@@ -63,7 +69,9 @@ public class PasswordManagerLauncher {
         }
 
         SettingsLauncher settingsLauncher = new SettingsLauncherImpl();
-        settingsLauncher.launchSettingsActivity(activity, PasswordSettings.class);
+        Bundle fragmentArgs = new Bundle();
+        fragmentArgs.putInt(MANAGE_PASSWORDS_REFERRER, referrer);
+        settingsLauncher.launchSettingsActivity(activity, PasswordSettings.class, fragmentArgs);
     }
 
     @CalledByNative

chrome/android/java/src/org/chromium/chrome/browser/password_manager/settings/PasswordSettings.java

@@ -16,6 +16,7 @@ import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 
+import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import androidx.appcompat.widget.Toolbar;
 import androidx.fragment.app.FragmentManager;
@@ -32,6 +33,8 @@ import org.chromium.chrome.browser.help.HelpAndFeedback;
 import org.chromium.chrome.browser.password_check.PasswordCheck;
 import org.chromium.chrome.browser.password_check.PasswordCheckFactory;
 import org.chromium.chrome.browser.password_check.PasswordCheckPreference;
+import org.chromium.chrome.browser.password_check.PasswordCheckReferrer;
+import org.chromium.chrome.browser.password_manager.ManagePasswordsReferrer;
 import org.chromium.chrome.browser.password_manager.PasswordManagerLauncher;
 import org.chromium.chrome.browser.preferences.Pref;
 import org.chromium.chrome.browser.profiles.Profile;
@@ -108,6 +111,9 @@ public class PasswordSettings
     private boolean mSearchRecorded;
     private Menu mMenu;
 
+    private @Nullable PasswordCheck mPasswordCheck;
+    private @ManagePasswordsReferrer int mManagePasswordsReferrer;
+
     /**
      * For controlling the UX flow of exporting passwords.
      */
@@ -141,6 +147,12 @@ public class PasswordSettings
 
         setHasOptionsMenu(true); // Password Export might be optional but Search is always present.
 
+        Bundle extras = getArguments();
+        assert extras.containsKey(PasswordManagerLauncher.MANAGE_PASSWORDS_REFERRER)
+            : "PasswordSettings must be launched with a manage-passwords-referrer fragment"
+                + "argument, but none was provided.";
+        mManagePasswordsReferrer = extras.getInt(PasswordManagerLauncher.MANAGE_PASSWORDS_REFERRER);
+
         if (savedInstanceState == null) return;
 
         if (savedInstanceState.containsKey(SAVED_STATE_SEARCH_QUERY)) {
@@ -149,6 +161,12 @@ public class PasswordSettings
         }
     }
 
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        mPasswordCheck = PasswordCheckFactory.getOrCreate();
+    }
+
     @Override
     public void onViewCreated(View view, Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -240,8 +258,7 @@ public class PasswordSettings
         if (mSearchQuery == null) {
             createSavePasswordsSwitch();
             createAutoSignInCheckbox();
-            if (ChromeFeatureList.isEnabled(ChromeFeatureList.PASSWORD_CHECK)
-                    && PasswordUIView.hasAccountForLeakCheckRequest()) {
+            if (mPasswordCheck != null) {
                 createCheckPasswords();
             }
         }
@@ -405,6 +422,13 @@ public class PasswordSettings
     public void onDestroy() {
         super.onDestroy();
         PasswordManagerHandlerProvider.getInstance().removeObserver(this);
+        // The component should only be destroyed when the activity has been closed by the user
+        // (e.g. by pressing on the back button) and not when the activity is temporarily destroyed
+        // by the system.
+        if (getActivity().isFinishing() && mPasswordCheck != null
+                && mManagePasswordsReferrer != ManagePasswordsReferrer.CHROME_SETTINGS) {
+            PasswordCheckFactory.destroy();
+        }
     }
 
     /**
@@ -486,8 +510,8 @@ public class PasswordSettings
         mCheckPasswords.setOnPreferenceClickListener(preference -> {
             getPrefService().setInteger(
                     Pref.SETTINGS_LAUNCHED_PASSWORD_CHECKS, numCheckLaunched + 1);
-            PasswordCheck passwordCheck = PasswordCheckFactory.create();
-            passwordCheck.showUi(getStyledContext());
+            PasswordCheck passwordCheck = PasswordCheckFactory.getOrCreate();
+            passwordCheck.showUi(getStyledContext(), PasswordCheckReferrer.PASSWORD_SETTINGS);
             // Return true to notify the click was handled
             return true;
         });

chrome/android/java/src/org/chromium/chrome/browser/settings/MainSettings.java

@@ -11,6 +11,7 @@ import android.os.Handler;
 import android.provider.Settings;
 import android.view.View;
 
+import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceFragmentCompat;
@@ -23,6 +24,8 @@ import org.chromium.chrome.browser.homepage.HomepageManager;
 import org.chromium.chrome.browser.net.spdyproxy.DataReductionProxySettings;
 import org.chromium.chrome.browser.night_mode.NightModeUtils;
 import org.chromium.chrome.browser.offlinepages.prefetch.PrefetchConfiguration;
+import org.chromium.chrome.browser.password_check.PasswordCheck;
+import org.chromium.chrome.browser.password_check.PasswordCheckFactory;
 import org.chromium.chrome.browser.password_manager.ManagePasswordsReferrer;
 import org.chromium.chrome.browser.password_manager.PasswordManagerLauncher;
 import org.chromium.chrome.browser.profiles.Profile;
@@ -75,6 +78,7 @@ public class MainSettings extends PreferenceFragmentCompat
     private final Map<String, Preference> mAllPreferences = new HashMap<>();
     private SignInPreference mSignInPreference;
     private ChromeBasePreference mManageSync;
+    private @Nullable PasswordCheck mPasswordCheck;
 
     public MainSettings() {
         setHasOptionsMenu(true);
@@ -86,6 +90,12 @@ public class MainSettings extends PreferenceFragmentCompat
         createPreferences();
     }
 
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        mPasswordCheck = PasswordCheckFactory.getOrCreate();
+    }
+
     @Override
     public void onViewCreated(View view, Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
@@ -98,6 +108,10 @@ public class MainSettings extends PreferenceFragmentCompat
     public void onDestroy() {
         super.onDestroy();
         mSignInPreference.onPreferenceFragmentDestroyed();
+        // The component should only be destroyed when the activity has been closed by the user
+        // (e.g. by pressing on the back button) and not when the activity is temporarily destroyed
+        // by the system.
+        if (getActivity().isFinishing() && mPasswordCheck != null) PasswordCheckFactory.destroy();
     }
 
     @Override

chrome/android/javatests/src/org/chromium/chrome/browser/settings/MainSettingsFragmentTest.java

@@ -4,6 +4,7 @@
 
 package org.chromium.chrome.browser.settings;
 
+import android.app.Activity;
 import android.text.TextUtils;
 import android.view.View;
 
@@ -40,6 +41,8 @@ import org.chromium.chrome.browser.language.settings.LanguageSettings;
 import org.chromium.chrome.browser.night_mode.NightModeUtils;
 import org.chromium.chrome.browser.night_mode.settings.ThemeSettingsFragment;
 import org.chromium.chrome.browser.notifications.settings.NotificationSettings;
+import org.chromium.chrome.browser.password_check.PasswordCheck;
+import org.chromium.chrome.browser.password_check.PasswordCheckFactory;
 import org.chromium.chrome.browser.password_manager.settings.PasswordSettings;
 import org.chromium.chrome.browser.privacy.settings.PrivacySettings;
 import org.chromium.chrome.browser.safety_check.SafetyCheckSettingsFragment;
@@ -58,6 +61,7 @@ import org.chromium.chrome.test.util.browser.sync.SyncTestUtil;
 import org.chromium.components.browser_ui.site_settings.SiteSettings;
 import org.chromium.components.search_engines.TemplateUrl;
 import org.chromium.components.search_engines.TemplateUrlService;
+import org.chromium.content_public.browser.test.util.CriteriaHelper;
 import org.chromium.content_public.browser.test.util.TestThreadUtils;
 
 import java.io.IOException;
@@ -93,6 +97,9 @@ public class MainSettingsFragmentTest {
     @Mock
     public TemplateUrl mMockSearchEngine;
 
+    @Mock
+    private PasswordCheck mPasswordCheck;
+
     private @Nullable TemplateUrlService mActualTemplateUrlService;
 
     private MainSettings mMainSettings;
@@ -100,6 +107,7 @@ public class MainSettingsFragmentTest {
     @Before
     public void setup() {
         MockitoAnnotations.initMocks(this);
+        PasswordCheckFactory.setPasswordCheckForTesting(mPasswordCheck);
         DeveloperSettings.setIsEnabledForTests(true);
         NightModeUtils.setNightModeSupportedForTesting(true);
     }
@@ -365,6 +373,17 @@ public class MainSettingsFragmentTest {
                 mMainSettings.findPreference(MainSettings.PREF_DEVELOPER));
     }
 
+    @Test
+    @SmallTest
+    @EnableFeatures({ChromeFeatureList.PASSWORD_CHECK})
+    public void testDestroysPasswordCheck() {
+        launchSettingsActivity();
+        Activity activity = mMainSettings.getActivity();
+        activity.finish();
+        CriteriaHelper.pollInstrumentationThread(() -> activity.isDestroyed());
+        Assert.assertNull(PasswordCheckFactory.getPasswordCheckInstance());
+    }
+
     /**
      * Assert the target preference exists in the main settings and creates the expected fragment,
      * then return that preference.

chrome/browser/password_check/android/BUILD.gn

@@ -39,6 +39,7 @@ android_library("public_java") {
     "java/src/org/chromium/chrome/browser/password_check/PasswordCheck.java",
     "java/src/org/chromium/chrome/browser/password_check/PasswordCheckFragmentView.java",
     "java/src/org/chromium/chrome/browser/password_check/PasswordCheckPreference.java",
+    "java/src/org/chromium/chrome/browser/password_check/PasswordCheckReferrer.java",
   ]
   resources_package = "org.chromium.chrome.browser.password_check"
 }
@@ -72,7 +73,10 @@ junit_binary("password_check_junit_tests") {
 android_library("test_java") {
   testonly = true
 
-  sources = [ "javatests/src/org/chromium/chrome/browser/password_check/PasswordCheckViewTest.java" ]
+  sources = [
+    "javatests/src/org/chromium/chrome/browser/password_check/PasswordCheckIntegrationTest.java",
+    "javatests/src/org/chromium/chrome/browser/password_check/PasswordCheckViewTest.java",
+  ]
 
   deps = [
     ":public_java",
@@ -85,6 +89,7 @@ android_library("test_java") {
     "//chrome/android:chrome_test_java",
     "//chrome/android:chrome_test_util_java",
     "//chrome/browser/flags:java",
+    "//chrome/browser/password_check/android/internal:public_factory_java",
     "//chrome/browser/settings:test_support_java",
     "//chrome/test/android:chrome_java_test_support",
     "//components/browser_ui/widget/android:java",
@@ -102,6 +107,7 @@ android_library("test_java") {
     "//ui/android:ui_utils_java",
   ]
 }
+
 android_resources("java_resources") {
   sources = [
     "java/res/drawable-night/password_check_neutral.xml",

chrome/browser/password_check/android/internal/BUILD.gn

@@ -20,7 +20,12 @@ android_library_factory("public_factory_java") {
 }
 
 android_library("internal_factory_java") {
-  deps = [ ":internal_java" ]
+  deps = [
+    ":internal_java",
+    "//chrome/browser/flags:java",
+    "//third_party/android_deps:androidx_annotation_annotation_java",
+    _public_target,
+  ]
   sources = _factory_sources
 }
 

chrome/browser/password_check/android/internal/java/src/org/chromium/chrome/browser/password_check/PasswordCheckBridge.java

@@ -11,7 +11,7 @@ import org.chromium.base.annotations.NativeMethods;
  * messages to and from its C++ counterpart.
  */
 class PasswordCheckBridge {
-    private final long mNativePasswordCheckBridge;
+    private long mNativePasswordCheckBridge;
     private final PasswordCheckObserver mPasswordCheckObserver;
 
     /**
@@ -88,6 +88,16 @@ class PasswordCheckBridge {
                 mNativePasswordCheckBridge, credentials);
     }
 
+    /**
+     * Destroys its C++ counterpart.
+     */
+    void destroy() {
+        if (mNativePasswordCheckBridge != 0) {
+            mNativePasswordCheckBridge = 0;
+            PasswordCheckBridgeJni.get().destroy(mNativePasswordCheckBridge);
+        }
+    }
+
     /**
      * C++ method signatures.
      */

chrome/browser/password_check/android/internal/java/src/org/chromium/chrome/browser/password_check/PasswordCheckCoordinator.java

@@ -49,7 +49,7 @@ class PasswordCheckCoordinator implements PasswordCheckComponentUi, LifecycleObs
             mModel = PasswordCheckProperties.createDefaultModel();
             PasswordCheckMediator mediator = new PasswordCheckMediator();
             PasswordCheckCoordinator.setUpModelChangeProcessors(mModel, mFragmentView);
-            mediator.initialize(mModel, PasswordCheckFactory.create());
+            mediator.initialize(mModel, PasswordCheckFactory.getOrCreate());
         }
     }
 
@@ -66,6 +66,11 @@ class PasswordCheckCoordinator implements PasswordCheckComponentUi, LifecycleObs
         return false;
     }
 
+    @Override
+    public void destroy() {
+        PasswordCheckFactory.destroy();
+    }
+
     /**
      * Connects the given model with the given view using Model Change Processors.
      * @param model A {@link PropertyModel} built with {@link PasswordCheckProperties}.

chrome/browser/password_check/android/internal/java/src/org/chromium/chrome/browser/password_check/PasswordCheckFactory.java

@@ -4,21 +4,52 @@
 
 package org.chromium.chrome.browser.password_check;
 
+import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
+
+import org.chromium.chrome.browser.flags.ChromeFeatureList;
+
 /**
- * Use {@link #create()} to instantiate a {@link PasswordCheckImpl}.
+ * Use {@link #getOrCreate()} to instantiate a {@link PasswordCheckImpl}
+ * and {@link #destroy()} when the instance is no longer needed.
  */
 public class PasswordCheckFactory {
     private static PasswordCheck sPasswordCheck;
     private PasswordCheckFactory() {}
 
     /**
-     * Creates a {@link PasswordCheckImpl}.
-     * @return A {@link PasswordCheckImpl}.
+     * Creates a {@link PasswordCheckImpl} if none exists. Otherwise it returns the existing
+     * instance.
+     * @return A {@link PasswordCheckImpl} or null if the feature is disabled.
      */
-    public static PasswordCheck create() {
+    public static @Nullable PasswordCheck getOrCreate() {
+        if (!ChromeFeatureList.isEnabled(ChromeFeatureList.PASSWORD_CHECK)) return null;
         if (sPasswordCheck == null) {
             sPasswordCheck = new PasswordCheckImpl();
         }
         return sPasswordCheck;
     }
-}
+
\ No newline at end of file
+    /**
+     * Destroys the C++ layer to free up memory. In order to not leave a partially initialized
+     * feature component alive, it sets the {@link PasswordCheckImpl} to null.
+     *
+     * Should be called by the last object alive who needs the feature. This is, in general,
+     * the outermost settings screen. Note that this is not always {@link MainSettings}.
+     */
+    public static void destroy() {
+        if (sPasswordCheck == null) return;
+        sPasswordCheck.destroy();
+        sPasswordCheck = null;
+    }
+
+    @VisibleForTesting
+    public static void setPasswordCheckForTesting(PasswordCheck passwordCheck) {
+        sPasswordCheck = passwordCheck;
+    }
+
+    @VisibleForTesting
+    public static PasswordCheck getPasswordCheckInstance() {
+        return sPasswordCheck;
+    }
+}

chrome/browser/password_check/android/internal/java/src/org/chromium/chrome/browser/password_check/PasswordCheckImpl.java

@@ -5,18 +5,44 @@
 package org.chromium.chrome.browser.password_check;
 
 import android.content.Context;
+import android.os.Bundle;
 
+import org.chromium.chrome.browser.password_check.PasswordCheckBridge.PasswordCheckObserver;
 import org.chromium.chrome.browser.settings.SettingsLauncher;
 import org.chromium.chrome.browser.settings.SettingsLauncherImpl;
 
 /**
  * This class is responsible for managing the saved passwords check for signed-in users.
  */
-class PasswordCheckImpl implements PasswordCheck {
+class PasswordCheckImpl implements PasswordCheck, PasswordCheckObserver {
+    private final PasswordCheckBridge mPasswordCheckBridge;
+
+    PasswordCheckImpl() {
+        mPasswordCheckBridge = new PasswordCheckBridge(this);
+    }
+
     @Override
-    public void showUi(Context context) {
+    public void showUi(Context context, @PasswordCheckReferrer int passwordCheckReferrer) {
         SettingsLauncher launcher = new SettingsLauncherImpl();
-        launcher.launchSettingsActivity(context, PasswordCheckFragmentView.class);
+        Bundle fragmentArgs = new Bundle();
+        fragmentArgs.putInt(
+                PasswordCheckFragmentView.PASSWORD_CHECK_REFERRER, passwordCheckReferrer);
+        launcher.launchSettingsActivity(context, PasswordCheckFragmentView.class, fragmentArgs);
+    }
+
+    @Override
+    public void destroy() {
+        mPasswordCheckBridge.destroy();
+    }
+
+    @Override
+    public void onCompromisedCredentialFound(String originUrl, String username, String password) {
+        // TODO(crbug.com): Broadcast to registered observers.
+    }
+
+    @Override
+    public void onCompromisedCredentialsFetched(int count) {
+        // TODO(crbug.com): Broadcast to registered observers.
     }
 
     @Override

chrome/browser/password_check/android/java/src/org/chromium/chrome/browser/password_check/PasswordCheck.java

@@ -15,6 +15,12 @@ public interface PasswordCheck extends PasswordCheckComponentUi.Delegate {
     /**
      * Initializes the PasswordCheck UI and launches it.
      * @param context A {@link Context} to create views and retrieve resources.
+     * @param passwordCheckReferrer The place which launched the check UI.
      */
-    void showUi(Context context);
+    void showUi(Context context, @PasswordCheckReferrer int passwordCheckReferrer);
+
+    /**
+     * Cleans up the C++ part, thus removing the compromised credentials from memory.
+     */
+    void destroy();
 }

chrome/browser/password_check/android/java/src/org/chromium/chrome/browser/password_check/PasswordCheckComponentUi.java

@@ -26,4 +26,9 @@ interface PasswordCheckComponentUi {
      * @param item A {@link MenuItem}.
      */
     boolean handleHelp(MenuItem item);
+
+    /**
+     * Tears down the component when it's no longer needed.
+     */
+    void destroy();
 }

chrome/browser/password_check/android/java/src/org/chromium/chrome/browser/password_check/PasswordCheckFragmentView.java

@@ -14,7 +14,13 @@ import androidx.preference.PreferenceFragmentCompat;
  * This class is responsible for rendering the check passwords view in the settings menu.
  */
 public class PasswordCheckFragmentView extends PreferenceFragmentCompat {
+    // Key for the argument with which the PasswordsCheck fragment will be launched. The value for
+    // this argument should be part of the PasswordCheckReferrer enum, which contains
+    // all points of entry to the password check UI.
+    public static final String PASSWORD_CHECK_REFERRER = "password-check-referrer";
+
     private PasswordCheckComponentUi mComponentDelegate;
+    private @PasswordCheckReferrer int mPasswordCheckReferrer;
 
     /**
      * Set the delegate that handles view events which affect the state of the component.
@@ -28,6 +34,24 @@ public class PasswordCheckFragmentView extends PreferenceFragmentCompat {
     public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
         getActivity().setTitle(R.string.passwords_check_title);
         setPreferenceScreen(getPreferenceManager().createPreferenceScreen(getStyledContext()));
+        Bundle extras = getArguments();
+        assert extras.containsKey(PASSWORD_CHECK_REFERRER)
+            : "PasswordCheckFragmentView"
+                + "must be launched with a password-check-referrer fragment argument, but none was"
+                + "provided.";
+        mPasswordCheckReferrer = extras.getInt(PASSWORD_CHECK_REFERRER);
+    }
+
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        // The component should only be destroyed when the activity has been closed by the user
+        // (e.g. by pressing on the back button) and not when the activity is temporarily destroyed
+        // by the system.
+        if (getActivity().isFinishing()
+                && mPasswordCheckReferrer == PasswordCheckReferrer.LEAK_DIALOG) {
+            mComponentDelegate.destroy();
+        }
     }
 
     @Override

chrome/browser/password_check/android/java/src/org/chromium/chrome/browser/password_check/PasswordCheckReferrer.java

+// Copyright 2020 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.
+package org.chromium.chrome.browser.password_check;
+
+import androidx.annotation.IntDef;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@IntDef({PasswordCheckReferrer.PASSWORD_SETTINGS, PasswordCheckReferrer.SAFETY_CHECK,
+        PasswordCheckReferrer.LEAK_DIALOG})
+@Retention(RetentionPolicy.SOURCE)
+public @interface PasswordCheckReferrer {
+    /**
+     * Corresponds to the Settings > Passwords page.
+     */
+    int PASSWORD_SETTINGS = 0;
+    /**
+     * Corresponds to the safety check settings page.
+     */
+    int SAFETY_CHECK = 1;
+    /**
+     * Represents the leak dialog prompted to the user when they sign in with a credential
+     * which was part of a data breach;
+     */
+    int LEAK_DIALOG = 2;
+}

chrome/browser/password_check/android/javatests/src/org/chromium/chrome/browser/password_check/PasswordCheckIntegrationTest.java

+// Copyright 2020 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.
+
+package org.chromium.chrome.browser.password_check;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import android.os.Bundle;
+
+import androidx.test.filters.MediumTest;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestRule;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import org.chromium.base.test.util.CommandLineFlags;
+import org.chromium.base.test.util.JniMocker;
+import org.chromium.chrome.browser.flags.ChromeFeatureList;
+import org.chromium.chrome.browser.flags.ChromeSwitches;
+import org.chromium.chrome.browser.settings.SettingsActivity;
+import org.chromium.chrome.browser.settings.SettingsActivityTestRule;
+import org.chromium.chrome.test.ChromeJUnit4ClassRunner;
+import org.chromium.chrome.test.util.browser.Features;
+import org.chromium.chrome.test.util.browser.Features.EnableFeatures;
+import org.chromium.content_public.browser.test.util.CriteriaHelper;
+
+/**
+ * Integration test for the Password Check component, testing the interaction between sub-components
+ * of the password check feature as well as the creation and destruction of the component.
+ **/
+@RunWith(ChromeJUnit4ClassRunner.class)
+@CommandLineFlags.Add({ChromeSwitches.DISABLE_FIRST_RUN_EXPERIENCE})
+@EnableFeatures({ChromeFeatureList.PASSWORD_CHECK})
+public class PasswordCheckIntegrationTest {
+    @Rule
+    public final SettingsActivityTestRule<PasswordCheckFragmentView> mTestRule =
+            new SettingsActivityTestRule<>(PasswordCheckFragmentView.class);
+    @Rule
+    public TestRule mProcessor = new Features.JUnitProcessor();
+
+    @Rule
+    public final JniMocker mJniMocker = new JniMocker();
+
+    @Mock
+    private PasswordCheckBridge.Natives mPasswordCheckBridge;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mJniMocker.mock(PasswordCheckBridgeJni.TEST_HOOKS, mPasswordCheckBridge);
+    }
+
+    @Test
+    @MediumTest
+    public void testDestroysComponentIfFirstInSettingsStack() {
+        PasswordCheckFactory.getOrCreate();
+        SettingsActivity activity = setUpUiLaunchedFromDialog();
+        activity.finish();
+        CriteriaHelper.pollInstrumentationThread(() -> activity.isDestroyed());
+        assertNull(PasswordCheckFactory.getPasswordCheckInstance());
+    }
+
+    @Test
+    @MediumTest
+    public void testDoesNotDestroyComponentIfNotFirstInSettingsStack() {
+        PasswordCheckFactory.getOrCreate();
+        SettingsActivity activity = setUpUiLaunchedFromSettings();
+        activity.finish();
+        CriteriaHelper.pollInstrumentationThread(() -> activity.isDestroyed());
+        assertNotNull(PasswordCheckFactory.getPasswordCheckInstance());
+        // Clean up the password check component.
+        PasswordCheckFactory.destroy();
+    }
+
+    private SettingsActivity setUpUiLaunchedFromSettings() {
+        Bundle fragmentArgs = new Bundle();
+        fragmentArgs.putInt(PasswordCheckFragmentView.PASSWORD_CHECK_REFERRER,
+                PasswordCheckReferrer.PASSWORD_SETTINGS);
+        SettingsActivity activity = mTestRule.startSettingsActivity(fragmentArgs);
+
+        return activity;
+    }
+
+    private SettingsActivity setUpUiLaunchedFromDialog() {
+        Bundle fragmentArgs = new Bundle();
+        fragmentArgs.putInt(PasswordCheckFragmentView.PASSWORD_CHECK_REFERRER,
+                PasswordCheckReferrer.LEAK_DIALOG);
+        SettingsActivity activity = mTestRule.startSettingsActivity(fragmentArgs);
+
+        return activity;
+    }
+}
\ No newline at end of file

chrome/browser/password_check/android/javatests/src/org/chromium/chrome/browser/password_check/PasswordCheckViewTest.java

@@ -23,6 +23,7 @@ import static org.chromium.chrome.browser.password_check.PasswordCheckProperties
 import static org.chromium.content_public.browser.test.util.CriteriaHelper.pollUiThread;
 import static org.chromium.content_public.browser.test.util.TestThreadUtils.runOnUiThreadBlocking;
 
+import android.os.Bundle;
 import android.view.View;
 import android.widget.ImageButton;
 import android.widget.TextView;
@@ -67,6 +68,7 @@ public class PasswordCheckViewTest {
 
     private PropertyModel mModel = PasswordCheckProperties.createDefaultModel();
     private PasswordCheckFragmentView mPasswordCheckView;
+
     @Mock
     private PasswordCheckComponentUi mComponentUi;
     @Mock
@@ -84,7 +86,7 @@ public class PasswordCheckViewTest {
             mPasswordCheckView.setComponentDelegate(mComponentUi);
             return mComponentUi;
         });
-        mTestRule.startSettingsActivity();
+        setUpUiLaunchedFromSettings();
         runOnUiThreadBlocking(() -> {
             PasswordCheckCoordinator.setUpModelChangeProcessors(mModel, mPasswordCheckView);
         });
@@ -182,6 +184,13 @@ public class PasswordCheckViewTest {
                         .build());
     }
 
+    private void setUpUiLaunchedFromSettings() {
+        Bundle fragmentArgs = new Bundle();
+        fragmentArgs.putInt(PasswordCheckFragmentView.PASSWORD_CHECK_REFERRER,
+                PasswordCheckReferrer.PASSWORD_SETTINGS);
+        mTestRule.startSettingsActivity(fragmentArgs);
+    }
+
     private View getStatus() {
         return mPasswordCheckView.getListView().getChildAt(0);
     }