[Android password settings] Display warning before export

This CL adds a warning to be displayed before the user can export
their passwords.

Mocks:
https://docs.google.com/presentation/d/1nIm5OmaOnb85ZAwMZPSVqHT0vkFbsRYZhOzbmznWU_c/edit#slide=id.g289b1efcd8_0_21

Note: the mock shows slightly different styling, but with the UX
designer we settled on using a standard dialog style already existing
in Chromium and checking separately whether that style needs fixing,
rather than introducing inconsistent styling among Chrome's dialogs.

Design: go chrome-pwd-export

Screenshot: https://crbug.com/788701#c7

Bug: 788701
Change-Id: I3a2dbdc24429c5662fdc2b178630a8e45ba603a1
Reviewed-on: https://chromium-review.googlesource.com/803955
Commit-Queue: Vaclav Brozek <vabr@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522062}

chrome/android/java/src/org/chromium/chrome/browser/preferences/password/ExportWarningDialogFragment.java

+// Copyright 2017 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.preferences.password;
+
+import android.app.Dialog;
+import android.app.DialogFragment;
+import android.content.DialogInterface;
+import android.os.Bundle;
+import android.support.v7.app.AlertDialog;
+
+import org.chromium.chrome.R;
+
+/**
+ * Shows the dialog that gives the user some tips for how to treat the exported passwords securely.
+ */
+public class ExportWarningDialogFragment extends DialogFragment {
+    // This handler is used to answer the user actions on the dialog.
+    private DialogInterface.OnClickListener mHandler;
+
+    public void setExportWarningHandler(DialogInterface.OnClickListener handler) {
+        mHandler = handler;
+    }
+
+    /**
+     * Opens the dialog with the warning and sets the button listener to a fragment identified by ID
+     * passed in arguments.
+     */
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        return new AlertDialog.Builder(getActivity(), R.style.SimpleDialog)
+                .setPositiveButton(R.string.save_password_preferences_export_action_title, mHandler)
+                .setNegativeButton(R.string.cancel, mHandler)
+                .setMessage(getActivity().getResources().getString(
+                        R.string.settings_passwords_export_description))
+                .create();
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        // If there is savedInstanceState, then the dialog is being recreated by Android and will
+        // lack the necessary callbacks. Dismiss immediately as the settings page will need to be
+        // recreated anyway.
+        if (savedInstanceState != null) {
+            dismiss();
+            return;
+        }
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/preferences/password/SavePasswordsPreferences.java

@@ -4,6 +4,7 @@
 
 package org.chromium.chrome.browser.preferences.password;
 
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
@@ -12,6 +13,7 @@ import android.preference.Preference.OnPreferenceChangeListener;
 import android.preference.PreferenceCategory;
 import android.preference.PreferenceFragment;
 import android.preference.PreferenceScreen;
+import android.support.v7.app.AlertDialog;
 import android.text.SpannableString;
 import android.text.style.ForegroundColorSpan;
 import android.view.Menu;
@@ -127,7 +129,21 @@ public class SavePasswordsPreferences
 
     /** Continues with the password export flow after the user successfully reauthenticated. */
     private void exportAfterReauth() {
-        // TODO(crbug.com/788701): Show the warning, start the export.
+        ExportWarningDialogFragment exportWarningDialogFragment = new ExportWarningDialogFragment();
+        exportWarningDialogFragment.setExportWarningHandler(new DialogInterface.OnClickListener() {
+            /** On positive button response asks the parent to continue with the export flow. */
+            @Override
+            public void onClick(DialogInterface dialog, int which) {
+                if (which == AlertDialog.BUTTON_POSITIVE) {
+                    exportAfterWarning();
+                }
+            }
+        });
+        exportWarningDialogFragment.show(getFragmentManager(), null);
+    }
+
+    private void exportAfterWarning() {
+        // TODO(crbug.com/788701): Start the export.
     }
 
     /**

chrome/android/java/strings/android_chrome_strings.grd

@@ -485,6 +485,9 @@ CHAR-LIMIT guidelines:
       <message name="IDS_SAVE_PASSWORD_PREFERENCES_EXPORT_ACTION_DESCRIPTION" desc="The description of a menu item to trigger exporting passwords from the password settings.">
         Export passwords stored with Chrome
       </message>
+      <message name="IDS_SETTINGS_PASSWORDS_EXPORT_DESCRIPTION" desc="Text shown to the user who initiated exporting passwords, as a warning before any passwords have been exported.">
+        Your passwords will be visible to anyone who can see the exported passwords file.
+      </message>
 
       <!-- Lock Screen Fragment -->
       <message name="IDS_LOCKSCREEN_DESCRIPTION_COPY" desc="When a user attempts to copy a password for a particular website into clipboard in Chrome's settings, Chrome launches a lock screen to verify the user's identity and displays the following explanation.">

chrome/android/java_sources.gni

@@ -968,6 +968,7 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/preferences/languages/LanguageItem.java",
   "java/src/org/chromium/chrome/browser/preferences/languages/LanguageListBaseAdapter.java",
   "java/src/org/chromium/chrome/browser/preferences/languages/LanguageListPreference.java",
+  "java/src/org/chromium/chrome/browser/preferences/password/ExportWarningDialogFragment.java",
   "java/src/org/chromium/chrome/browser/preferences/password/PasswordEntryEditor.java",
   "java/src/org/chromium/chrome/browser/preferences/password/PasswordManagerHandlerProvider.java",
   "java/src/org/chromium/chrome/browser/preferences/password/PasswordReauthenticationFragment.java",

chrome/android/javatests/src/org/chromium/chrome/browser/preferences/password/SavePasswordsPreferencesTest.java

@@ -244,7 +244,8 @@ public class SavePasswordsPreferencesTest {
     }
 
     /**
-     * Ensure that the export menu item is included and hidden behind the overflow menu.
+     * Check that the export menu item is included and hidden behind the overflow menu. Check that
+     * the menu displays the warning before letting the user export passwords.
      */
     @Test
     @SmallTest
@@ -261,8 +262,14 @@ public class SavePasswordsPreferencesTest {
 
         Espresso.openActionBarOverflowOrOptionsMenu(
                 InstrumentationRegistry.getInstrumentation().getTargetContext());
+        // Before tapping the menu item for export, pretend that the last successful
+        // reauthentication just happened. This will allow the export flow to continue.
+        ReauthenticationManager.setLastReauthTimeMillis(System.currentTimeMillis());
         Espresso.onView(withText(R.string.save_password_preferences_export_action_title))
                 .perform(click());
+
+        Espresso.onView(withText(R.string.settings_passwords_export_description))
+                .check(matches(isDisplayed()));
     }
 
     /**