[PwdCheckAndroid] Disable save button for empty passwords

With this CL, the save button is disabled while the new password is
empty. Additionally, it displays a brief error text to inform the user
about the required field.

Screenshots in the bug.

Bug: 1114720, 1092444
Change-Id: I0abb9582bdde093a69279a6887b74c0ddea68436
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2359995Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Commit-Queue: Friedrich [CET] <fhorschig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799047}

chrome/browser/password_check/android/BUILD.gn

@@ -125,6 +125,7 @@ android_library("test_java") {
     "//third_party/android_deps:androidx_recyclerview_recyclerview_java",
     "//third_party/android_deps:androidx_test_runner_java",
     "//third_party/android_deps:espresso_java",
+    "//third_party/android_deps:material_design_java",
     "//third_party/android_sdk:android_test_base_java",
     "//third_party/hamcrest:hamcrest_java",
     "//third_party/junit",
@@ -155,6 +156,9 @@ android_resources("java_resources") {
     "java/res/values-night/colors.xml",
     "java/res/values/colors.xml",
   ]
-  deps = [ "//chrome/browser/ui/android/strings:ui_strings_grd" ]
+  deps = [
+    "//chrome/browser/ui/android/strings:ui_strings_grd",
+    "//components/strings:components_strings_grd",
+  ]
   create_srcjar = false
 }

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

@@ -21,6 +21,8 @@ import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import androidx.preference.PreferenceFragmentCompat;
 
+import com.google.android.material.textfield.TextInputLayout;
+
 import org.chromium.base.supplier.Supplier;
 
 /**
@@ -38,6 +40,8 @@ public class PasswordCheckEditFragmentView extends PreferenceFragmentCompat {
     private CompromisedCredential mCredential;
 
     private EditText mPasswordText;
+    private MenuItem mSaveButton;
+    private TextInputLayout mPasswordLabel;
 
     /**
      * Initializes the password check factory that allows to retrieve a {@link PasswordCheck}
@@ -71,6 +75,7 @@ public class PasswordCheckEditFragmentView extends PreferenceFragmentCompat {
         EditText usernameText = (EditText) view.findViewById(R.id.username_edit);
         usernameText.setText(mCredential.getDisplayUsername());
 
+        mPasswordLabel = (TextInputLayout) view.findViewById(R.id.password_label);
         mPasswordText = (EditText) view.findViewById(R.id.password_edit);
         mPasswordText.setText(mCredential.getPassword());
         mPasswordText.addTextChangedListener(new TextWatcher() {
@@ -83,17 +88,19 @@ public class PasswordCheckEditFragmentView extends PreferenceFragmentCompat {
             @Override
             public void afterTextChanged(Editable editable) {
                 mNewPassword = mPasswordText.getText().toString();
-                if (TextUtils.isEmpty(mNewPassword)) {
-                    // TODO(crbug.com/1114720): setError on R.id.password_label.
-                }
+                checkSavingConditions(TextUtils.isEmpty(mNewPassword));
             }
         });
+        // Enforce that even the initial password (maybe from a saved instance) cannot be empty.
+        checkSavingConditions(TextUtils.isEmpty(mNewPassword));
     }
 
     @Override
     public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
         menu.clear(); // Remove help and feedback for this screen.
         inflater.inflate(R.menu.password_check_editor_action_bar_menu, menu);
+        mSaveButton = menu.findItem(R.id.action_save_edited_password);
+        checkSavingConditions(mNewPassword.isEmpty()); // Enable the newly created save button.
         // TODO(crbug.com/1092444): Make the back arrow an 'X'.
     }
 
@@ -108,7 +115,7 @@ public class PasswordCheckEditFragmentView extends PreferenceFragmentCompat {
     public boolean onOptionsItemSelected(MenuItem item) {
         int id = item.getItemId();
         if (id == R.id.action_save_edited_password) {
-            if (!TextUtils.isEmpty(mNewPassword)) saveChanges();
+            saveChanges();
             return true;
         }
         return super.onOptionsItemSelected(item);
@@ -144,4 +151,11 @@ public class PasswordCheckEditFragmentView extends PreferenceFragmentCompat {
         }
         return mCredential.getPassword();
     }
+
+    private void checkSavingConditions(boolean emptyPassword) {
+        if (mSaveButton != null) mSaveButton.setEnabled(!emptyPassword);
+        mPasswordLabel.setError(emptyPassword ? getContext().getString(
+                                        R.string.pref_edit_dialog_field_required_validation_message)
+                                              : "");
+    }
 }

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

@@ -6,11 +6,14 @@ package org.chromium.chrome.browser.password_check;
 
 import static androidx.test.espresso.Espresso.onView;
 import static androidx.test.espresso.action.ViewActions.click;
+import static androidx.test.espresso.assertion.ViewAssertions.matches;
+import static androidx.test.espresso.matcher.ViewMatchers.isEnabled;
 import static androidx.test.espresso.matcher.ViewMatchers.withId;
 
 import static junit.framework.Assert.assertTrue;
 
 import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.not;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThat;
 import static org.mockito.ArgumentMatchers.eq;
@@ -25,8 +28,11 @@ import android.os.Bundle;
 import android.text.InputType;
 import android.widget.EditText;
 
+import androidx.annotation.StringRes;
 import androidx.test.filters.MediumTest;
 
+import com.google.android.material.textfield.TextInputLayout;
+
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -130,10 +136,29 @@ public class PasswordCheckEditViewTest {
         verify(mPasswordCheck).updateCredential(eq(ANA), eq(newPassword));
     }
 
+    @Test
+    @MediumTest
+    public void testEmptyPasswordDisablesSaveButton() {
+        // Delete the password.
+        EditText password = mPasswordCheckEditView.getView().findViewById(R.id.password_edit);
+        runOnUiThreadBlocking(() -> password.setText(""));
+
+        onView(withId(R.id.action_save_edited_password)).check(matches(not(isEnabled())));
+        TextInputLayout passwordLabel =
+                mPasswordCheckEditView.getView().findViewById(R.id.password_label);
+        assertNotNull(passwordLabel.getError());
+        assertThat(passwordLabel.getError().toString(),
+                equalTo(getString(R.string.pref_edit_dialog_field_required_validation_message)));
+    }
+
     private void setUpUiLaunchedFromSettings() {
         Bundle fragmentArgs = new Bundle();
         fragmentArgs.putParcelable(EXTRA_COMPROMISED_CREDENTIAL, ANA);
         mTestRule.startSettingsActivity(fragmentArgs);
         mPasswordCheckEditView = mTestRule.getFragment();
     }
+
+    private String getString(@StringRes int stringId) {
+        return mPasswordCheckEditView.getContext().getString(stringId);
+    }
 }