Add disable by default feature flag for login display password button

This CL reintroduces the submit button on the login / lock screen password textfield and disable the login display password button feature by default, by putting it under a feature flag.

Bug: 1090319
Change-Id: I521a19262726f7c0566d824b0efe5aa1c9abb7a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2247826
Commit-Queue: Thomas Tellier <tellier@google.com>
Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#780311}

ash/login/ui/login_auth_user_view.cc

@@ -35,6 +35,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/timer/timer.h"
+#include "chromeos/constants/chromeos_features.h"
 #include "components/user_manager/user.h"
 #include "ui/accessibility/ax_enums.mojom.h"
 #include "ui/accessibility/ax_node_data.h"
@@ -824,14 +825,26 @@ LoginAuthUserView::LoginAuthUserView(const LoginUserInfo& user,
   password_view_->SetDisplayPasswordButtonVisible(
       user.show_display_password_button);
 
-  auto pin_view = std::make_unique<LoginPinView>(
-      LoginPinView::Style::kAlphanumeric,
-      base::BindRepeating(&LoginPasswordView::InsertNumber,
-                          base::Unretained(password_view.get())),
-      base::BindRepeating(&LoginPasswordView::Backspace,
-                          base::Unretained(password_view.get())),
-      base::BindRepeating(&LoginPasswordView::SubmitPassword,
-                          base::Unretained(password_view.get())));
+  std::unique_ptr<LoginPinView> pin_view;
+  // If the display password button feature is disabled, the PIN view does not
+  // need a submit button as the password view already has one.
+  if (chromeos::features::IsLoginDisplayPasswordButtonEnabled()) {
+    pin_view = std::make_unique<LoginPinView>(
+        LoginPinView::Style::kAlphanumeric,
+        base::BindRepeating(&LoginPasswordView::InsertNumber,
+                            base::Unretained(password_view.get())),
+        base::BindRepeating(&LoginPasswordView::Backspace,
+                            base::Unretained(password_view.get())),
+        base::BindRepeating(&LoginPasswordView::SubmitPassword,
+                            base::Unretained(password_view.get())));
+  } else {
+    pin_view = std::make_unique<LoginPinView>(
+        LoginPinView::Style::kAlphanumeric,
+        base::BindRepeating(&LoginPasswordView::InsertNumber,
+                            base::Unretained(password_view.get())),
+        base::BindRepeating(&LoginPasswordView::Backspace,
+                            base::Unretained(password_view.get())));
+  }
   pin_view_ = pin_view.get();
   DCHECK(pin_view_->layer());
 
@@ -985,7 +998,7 @@ void LoginAuthUserView::SetAuthMethods(uint32_t auth_methods,
 
   password_view_->SetEnabled(has_password);
   password_view_->SetEnabledOnEmptyPassword(has_tap);
-  password_view_->SetFocusEnabledOnTextfield(has_password);
+  password_view_->SetFocusEnabledForChildViews(has_password);
   password_view_->SetVisible(!hide_auth && has_password);
   password_view_->layer()->SetOpacity(has_password ? 1 : 0);
   password_view_container_->SetVisible(has_password || !has_challenge_response);

ash/login/ui/login_auth_user_view_unittest.cc

@@ -12,6 +12,8 @@
 #include "base/bind_helpers.h"
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_feature_list.h"
+#include "chromeos/constants/chromeos_features.h"
 #include "chromeos/dbus/power/fake_power_manager_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/events/event_utils.h"
@@ -198,6 +200,39 @@ TEST_F(LoginAuthUserViewUnittest, PasswordFieldChangeOnUpdateUser) {
   view_->UpdateForUser(user_);
   EXPECT_EQ(password_test.textfield()->GetText(), password);
 
+  auto another_user = CreateUser("user2@domain.com");
+  view_->UpdateForUser(another_user);
+  EXPECT_TRUE(password_test.textfield()->GetText().empty());
+}
+
+// LoginAuthUserViewUnittest with display password button feature enabled.
+class LoginAuthUserViewUnittestFeatureEnabled
+    : public LoginAuthUserViewUnittest {
+ protected:
+  LoginAuthUserViewUnittestFeatureEnabled() {
+    feature_list_.InitWithFeatures(
+        {chromeos::features::kLoginDisplayPasswordButton}, {});
+  }
+  LoginAuthUserViewUnittestFeatureEnabled(
+      const LoginAuthUserViewUnittestFeatureEnabled&) = delete;
+  LoginAuthUserViewUnittestFeatureEnabled& operator=(
+      const LoginAuthUserViewUnittestFeatureEnabled&) = delete;
+  ~LoginAuthUserViewUnittestFeatureEnabled() override = default;
+
+ private:
+  base::test::ScopedFeatureList feature_list_;
+};
+
+TEST_F(LoginAuthUserViewUnittestFeatureEnabled,
+       PasswordFieldChangeOnUpdateUser) {
+  LoginAuthUserView::TestApi test_auth_user_view(view_);
+  LoginPasswordView::TestApi password_test(test_auth_user_view.password_view());
+
+  const auto password = base::ASCIIToUTF16("abc1");
+  password_test.textfield()->SetText(password);
+  view_->UpdateForUser(user_);
+  EXPECT_EQ(password_test.textfield()->GetText(), password);
+
   auto another_user = CreateUser("user2@domain.com");
   view_->UpdateForUser(another_user);
   EXPECT_TRUE(password_test.textfield()->GetText().empty());

ash/login/ui/login_password_view.cc

@@ -8,6 +8,7 @@
 #include "ash/login/ui/horizontal_image_sequence_animation_decoder.h"
 #include "ash/login/ui/hover_notifier.h"
 #include "ash/login/ui/lock_screen.h"
+#include "ash/login/ui/login_button.h"
 #include "ash/login/ui/non_accessible_view.h"
 #include "ash/public/cpp/login_constants.h"
 #include "ash/public/cpp/login_types.h"
@@ -19,6 +20,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/timer/timer.h"
+#include "chromeos/constants/chromeos_features.h"
 #include "ui/accessibility/ax_enums.mojom.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -64,6 +66,9 @@ constexpr int kPasswordFontDeltaSize = 5;
 // Spacing between glyphs.
 constexpr int kPasswordGlyphSpacing = 6;
 
+// Size (width/height) of the submit button.
+constexpr int kSubmitButtonSizeDp = 20;
+
 // Size (width/height) of the display password button.
 constexpr int kDisplayPasswordButtonSizeDp = 20;
 
@@ -418,6 +423,7 @@ LoginPasswordView::TestApi::~TestApi() = default;
 
 void LoginPasswordView::TestApi::SubmitPassword(const std::string& password) {
   view_->textfield_->SetText(base::ASCIIToUTF16(password));
+  view_->UpdateUiState();
   view_->SubmitPassword();
 }
 
@@ -425,6 +431,10 @@ views::Textfield* LoginPasswordView::TestApi::textfield() const {
   return view_->textfield_;
 }
 
+views::View* LoginPasswordView::TestApi::submit_button() const {
+  return view_->submit_button_;
+}
+
 views::ToggleImageButton* LoginPasswordView::TestApi::display_password_button()
     const {
   return view_->display_password_button_;
@@ -448,7 +458,9 @@ void LoginPasswordView::TestApi::SetTimers(
 }
 
 LoginPasswordView::LoginPasswordView()
-    : clear_password_timer_(std::make_unique<base::RetainingOneShotTimer>()),
+    : is_display_password_feature_enabled_(
+          chromeos::features::IsLoginDisplayPasswordButtonEnabled()),
+      clear_password_timer_(std::make_unique<base::RetainingOneShotTimer>()),
       hide_password_timer_(std::make_unique<base::RetainingOneShotTimer>()) {
   Shell::Get()->ime_controller()->AddObserver(this);
 
@@ -504,9 +516,27 @@ LoginPasswordView::LoginPasswordView()
   // OnCapsLockChanged with the actual caps lock state.
   capslock_icon_->SetVisible(false);
 
-  // Display password button.
-  display_password_button_ = password_row_->AddChildView(
-      std::make_unique<DisplayPasswordButton>(this));
+  if (is_display_password_feature_enabled_) {
+    // Display password button.
+    display_password_button_ = password_row_->AddChildView(
+        std::make_unique<DisplayPasswordButton>(this));
+  } else {
+    // Submit button.
+    submit_button_ =
+        password_row_->AddChildView(std::make_unique<LoginButton>(this));
+    submit_button_->SetImage(
+        views::Button::STATE_NORMAL,
+        gfx::CreateVectorIcon(kLockScreenArrowIcon, kSubmitButtonSizeDp,
+                              login_constants::kButtonEnabledColor));
+    submit_button_->SetImage(
+        views::Button::STATE_DISABLED,
+        gfx::CreateVectorIcon(
+            kLockScreenArrowIcon, kSubmitButtonSizeDp,
+            SkColorSetA(login_constants::kButtonEnabledColor,
+                        login_constants::kButtonDisabledAlpha)));
+    submit_button_->SetAccessibleName(
+        l10n_util::GetStringUTF16(IDS_ASH_LOGIN_SUBMIT_BUTTON_ACCESSIBLE_NAME));
+  }
 
   // Separator on bottom.
   separator_ = AddChildView(std::make_unique<NonAccessibleSeparator>());
@@ -519,6 +549,9 @@ LoginPasswordView::LoginPasswordView()
 
   // Initialize with the initial state of caps lock.
   OnCapsLockChanged(Shell::Get()->ime_controller()->IsCapsLockEnabled());
+
+  // Make sure the UI start with the correct states.
+  UpdateUiState();
 }
 
 LoginPasswordView::~LoginPasswordView() {
@@ -540,6 +573,7 @@ void LoginPasswordView::Init(
 
 void LoginPasswordView::SetEnabledOnEmptyPassword(bool enabled) {
   enabled_on_empty_password_ = enabled;
+  UpdateUiState();
 }
 
 void LoginPasswordView::SetEasyUnlockIcon(
@@ -559,14 +593,16 @@ void LoginPasswordView::SetAccessibleName(const base::string16& name) {
   textfield_->SetAccessibleName(name);
 }
 
-void LoginPasswordView::SetFocusEnabledOnTextfield(bool enable) {
+void LoginPasswordView::SetFocusEnabledForChildViews(bool enable) {
   auto behavior = enable ? FocusBehavior::ALWAYS : FocusBehavior::NEVER;
   textfield_->SetFocusBehavior(behavior);
 }
 
 void LoginPasswordView::SetDisplayPasswordButtonVisible(bool visible) {
+  if (!is_display_password_feature_enabled_)
+    return;
   display_password_button_->SetVisible(visible);
-  // Only start the timer if the display password feature is enabled.
+  // Only start the timer if the display password button is enabled.
   if (visible) {
     clear_password_timer_->Start(
         FROM_HERE, kClearPasswordAfterDelay,
@@ -576,9 +612,12 @@ void LoginPasswordView::SetDisplayPasswordButtonVisible(bool visible) {
 
 void LoginPasswordView::Reset() {
   Clear();
-  // A user could hit the display button, then quickly switch account and
-  // type; we want the password to be hidden in such a case.
-  HidePassword(false /*chromevox_exception*/);
+
+  if (is_display_password_feature_enabled_) {
+    // A user could hit the display button, then quickly switch account and
+    // type; we want the password to be hidden in such a case.
+    HidePassword(false /*chromevox_exception*/);
+  }
 }
 
 void LoginPasswordView::Clear() {
@@ -620,6 +659,7 @@ void LoginPasswordView::SetPlaceholderText(
 void LoginPasswordView::SetReadOnly(bool read_only) {
   textfield_->SetReadOnly(read_only);
   textfield_->SetCursorEnabled(!read_only);
+  UpdateUiState();
 }
 
 const char* LoginPasswordView::GetClassName() const {
@@ -658,8 +698,13 @@ void LoginPasswordView::InvertPasswordDisplayingState() {
 
 void LoginPasswordView::ButtonPressed(views::Button* sender,
                                       const ui::Event& event) {
-  DCHECK_EQ(sender, display_password_button_);
-  InvertPasswordDisplayingState();
+  if (is_display_password_feature_enabled_) {
+    DCHECK_EQ(sender, display_password_button_);
+    InvertPasswordDisplayingState();
+  } else {
+    DCHECK_EQ(sender, submit_button_);
+    SubmitPassword();
+  }
 }
 
 void LoginPasswordView::HidePassword(bool chromevox_exception) {
@@ -674,7 +719,12 @@ void LoginPasswordView::HidePassword(bool chromevox_exception) {
 void LoginPasswordView::ContentsChanged(views::Textfield* sender,
                                         const base::string16& new_contents) {
   DCHECK_EQ(sender, textfield_);
+  UpdateUiState();
   on_password_text_changed_.Run(new_contents.empty() /*is_empty*/);
+
+  if (!is_display_password_feature_enabled_)
+    return;
+
   // Only reset the timer if the display password feature is enabled.
   if (display_password_button_->GetVisible())
     clear_password_timer_->Reset();
@@ -710,6 +760,11 @@ bool LoginPasswordView::HandleKeyEvent(views::Textfield* sender,
   return true;
 }
 
+void LoginPasswordView::UpdateUiState() {
+  if (!is_display_password_feature_enabled_)
+    submit_button_->SetEnabled(IsPasswordSubmittable());
+}
+
 void LoginPasswordView::OnCapsLockChanged(bool enabled) {
   capslock_icon_->SetVisible(enabled);
   password_row_->Layout();

ash/login/ui/login_password_view.h

@@ -26,14 +26,24 @@ class ToggleImageButton;
 }  // namespace views
 
 namespace ash {
+class LoginButton;
 enum class EasyUnlockIconId;
 
-// Contains a textfield instance with a display password button. The user can
-// type a password into the textfield and hit enter to submit.
+// Contains a textfield instance with a submit button when the display password
+// button feature is disabled, and a display password button otherwise. The user
+// can type a password into the textfield and hit enter to submit.
 //
 // This view is always rendered via layers.
 //
-// The password view looks like this by default:
+//
+// When the display password button feature is disabled, the password view looks
+// like this:
+//
+// * * * * * *     =>
+// ------------------
+//
+// When the display password button feature is enabled, the password view looks
+// like this by default:
 //
 //  * * * * * *    (\)
 //  ------------------
@@ -56,6 +66,7 @@ class ASH_EXPORT LoginPasswordView : public views::View,
     void SubmitPassword(const std::string& password);
 
     views::Textfield* textfield() const;
+    views::View* submit_button() const;
     views::ToggleImageButton* display_password_button() const;
     views::View* easy_unlock_icon() const;
     void set_immediately_hover_easy_unlock_icon();
@@ -77,7 +88,8 @@ class ASH_EXPORT LoginPasswordView : public views::View,
   LoginPasswordView();
   ~LoginPasswordView() override;
 
-  // |on_submit| is called when the user hits enter.
+  // |on_submit| is called when the user hits enter (or pressed the submit arrow
+  // when the display password button feature is disabled).
   // |on_password_text_changed| is called when the text in the password field
   // changes.
   void Init(const OnPasswordSubmit& on_submit,
@@ -95,8 +107,10 @@ class ASH_EXPORT LoginPasswordView : public views::View,
   // Set the textfield name used for accessibility.
   void SetAccessibleName(const base::string16& name);
 
-  // Enable or disable focus on the password field.
-  void SetFocusEnabledOnTextfield(bool enable);
+  // Enable or disable focus on the child elements (i.e.: password field, and
+  // submit button if the display password button feature is disabled, or
+  // display password button if the feature is enabled).
+  void SetFocusEnabledForChildViews(bool enable);
 
   // Sets whether the display password button is visible.
   void SetDisplayPasswordButtonVisible(bool visible);
@@ -118,7 +132,8 @@ class ASH_EXPORT LoginPasswordView : public views::View,
   // itself because it doesn't know which auth methods are enabled.
   void SetPlaceholderText(const base::string16& placeholder_text);
 
-  // Makes the textfield read-only.
+  // Makes the textfield read-only, and enables/disables submitting if the
+  // display password button feature is disabled.
   void SetReadOnly(bool read_only);
 
   // views::View:
@@ -167,9 +182,17 @@ class ASH_EXPORT LoginPasswordView : public views::View,
   // textfield is not empty or if |enabled_on_empty_password| is true.
   bool IsPasswordSubmittable();
 
+  // When the display password button feature is disabled, UpdateUiState
+  // enables/disables the submit button and changes the color of the separator
+  // based on if the view is enabled.
+  void UpdateUiState();
+
   OnPasswordSubmit on_submit_;
   OnPasswordTextChanged on_password_text_changed_;
 
+  // True if the display password button feature is enabled.
+  const bool is_display_password_feature_enabled_;
+
   // Is the password field enabled when there is no text?
   bool enabled_on_empty_password_ = false;
 
@@ -185,6 +208,7 @@ class ASH_EXPORT LoginPasswordView : public views::View,
   views::View* password_row_ = nullptr;
 
   LoginTextfield* textfield_ = nullptr;
+  LoginButton* submit_button_ = nullptr;
   DisplayPasswordButton* display_password_button_ = nullptr;
   views::ImageView* capslock_icon_ = nullptr;
   views::Separator* separator_ = nullptr;

ash/login/ui/login_password_view_test.cc

@@ -9,7 +9,9 @@
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_feature_list.h"
 #include "base/timer/mock_timer.h"
+#include "chromeos/constants/chromeos_features.h"
 #include "ui/base/ime/text_input_type.h"
 #include "ui/events/test/event_generator.h"
 #include "ui/views/controls/button/image_button.h"
@@ -62,10 +64,64 @@ class LoginPasswordViewTest : public LoginTestBase {
   DISALLOW_COPY_AND_ASSIGN(LoginPasswordViewTest);
 };
 
+// LoginPasswordViewTest with display password button feature enabled.
+class LoginPasswordViewTestFeatureEnabled : public LoginPasswordViewTest {
+ protected:
+  LoginPasswordViewTestFeatureEnabled() {
+    feature_list_.InitWithFeatures(
+        {chromeos::features::kLoginDisplayPasswordButton}, {});
+  }
+  LoginPasswordViewTestFeatureEnabled(
+      const LoginPasswordViewTestFeatureEnabled&) = delete;
+  LoginPasswordViewTestFeatureEnabled& operator=(
+      const LoginPasswordViewTestFeatureEnabled&) = delete;
+  ~LoginPasswordViewTestFeatureEnabled() override = default;
+
+ private:
+  base::test::ScopedFeatureList feature_list_;
+};
+
 }  // namespace
 
+// Verifies that the submit button updates its UI state.
+TEST_F(LoginPasswordViewTest, SubmitButtonUpdatesUiState) {
+  LoginPasswordView::TestApi test_api(view_);
+  ui::test::EventGenerator* generator = GetEventGenerator();
+
+  // The submit button starts with the disabled state.
+  EXPECT_TRUE(is_password_field_empty_);
+  EXPECT_FALSE(test_api.submit_button()->GetEnabled());
+  // Enter 'a'. The submit button is enabled.
+  generator->PressKey(ui::KeyboardCode::VKEY_A, 0);
+  EXPECT_FALSE(is_password_field_empty_);
+  EXPECT_TRUE(test_api.submit_button()->GetEnabled());
+  // Enter 'b'. The submit button stays enabled.
+  generator->PressKey(ui::KeyboardCode::VKEY_B, 0);
+  EXPECT_FALSE(is_password_field_empty_);
+  EXPECT_TRUE(test_api.submit_button()->GetEnabled());
+
+  // Clear password. The submit button is disabled.
+  view_->Clear();
+  EXPECT_TRUE(is_password_field_empty_);
+  EXPECT_FALSE(test_api.submit_button()->GetEnabled());
+
+  // Enter 'a'. The submit button is enabled.
+  generator->PressKey(ui::KeyboardCode::VKEY_A, 0);
+  EXPECT_FALSE(is_password_field_empty_);
+  EXPECT_TRUE(test_api.submit_button()->GetEnabled());
+  // Set the text field to be read-only. The submit button is disabled.
+  view_->SetReadOnly(true);
+  EXPECT_FALSE(is_password_field_empty_);
+  EXPECT_FALSE(test_api.submit_button()->GetEnabled());
+  // Set the text field to be not read-only. The submit button is enabled.
+  view_->SetReadOnly(false);
+  EXPECT_FALSE(is_password_field_empty_);
+  EXPECT_TRUE(test_api.submit_button()->GetEnabled());
+}
+
 // Verifies that the display password button updates its UI state.
-TEST_F(LoginPasswordViewTest, DisplayPasswordButtonUpdatesUiState) {
+TEST_F(LoginPasswordViewTestFeatureEnabled,
+       DisplayPasswordButtonUpdatesUiState) {
   LoginPasswordView::TestApi test_api(view_);
   ui::test::EventGenerator* generator = GetEventGenerator();
 
@@ -116,6 +172,23 @@ TEST_F(LoginPasswordViewTest, PasswordSubmitIncludesPasswordText) {
   EXPECT_EQ(base::ASCIIToUTF16("abc1"), *password_);
 }
 
+// Verifies that password submit works when clicking the submit button.
+TEST_F(LoginPasswordViewTest, PasswordSubmitViaButton) {
+  LoginPasswordView::TestApi test_api(view_);
+
+  ui::test::EventGenerator* generator = GetEventGenerator();
+  generator->PressKey(ui::KeyboardCode::VKEY_A, 0);
+  generator->PressKey(ui::KeyboardCode::VKEY_B, 0);
+  generator->PressKey(ui::KeyboardCode::VKEY_C, 0);
+  generator->PressKey(ui::KeyboardCode::VKEY_1, 0);
+  generator->MoveMouseTo(
+      test_api.submit_button()->GetBoundsInScreen().CenterPoint());
+  generator->ClickLeftButton();
+
+  ASSERT_TRUE(password_.has_value());
+  EXPECT_EQ(base::ASCIIToUTF16("abc1"), *password_);
+}
+
 // Verifies that text is not cleared after submitting a password.
 TEST_F(LoginPasswordViewTest, PasswordSubmitClearsPassword) {
   LoginPasswordView::TestApi test_api(view_);
@@ -211,7 +284,7 @@ TEST_F(LoginPasswordViewTest, CtrlZDisabled) {
 
 // Verifies that the password textfield clears after a delay when the display
 // password button is shown.
-TEST_F(LoginPasswordViewTest, PasswordAutoClearsAndHides) {
+TEST_F(LoginPasswordViewTestFeatureEnabled, PasswordAutoClearsAndHides) {
   LoginPasswordView::TestApi test_api(view_);
   ui::test::EventGenerator* generator = GetEventGenerator();
 
@@ -254,7 +327,7 @@ TEST_F(LoginPasswordViewTest, PasswordAutoClearsAndHides) {
 }
 
 // Verifies that the password textfield hides back when the content changes.
-TEST_F(LoginPasswordViewTest, PasswordHidesAfterTyping) {
+TEST_F(LoginPasswordViewTestFeatureEnabled, PasswordHidesAfterTyping) {
   LoginPasswordView::TestApi test_api(view_);
   ui::test::EventGenerator* generator = GetEventGenerator();
 
@@ -286,7 +359,7 @@ TEST_F(LoginPasswordViewTest, PasswordHidesAfterTyping) {
 
 // Checks that the display password button is disabled when the textfield is
 // empty and enabled when it is not.
-TEST_F(LoginPasswordViewTest,
+TEST_F(LoginPasswordViewTestFeatureEnabled,
        DisplayPasswordButonIsEnabledIFFTextfieldIsNotEmpty) {
   LoginPasswordView::TestApi test_api(view_);
   ui::test::EventGenerator* generator = GetEventGenerator();
@@ -318,7 +391,7 @@ TEST_F(LoginPasswordViewTest,
 }
 
 // Verifies that focus returned to the textfield after InsertNumber is called.
-TEST_F(LoginPasswordViewTest, FocusReturn) {
+TEST_F(LoginPasswordViewTestFeatureEnabled, FocusReturn) {
   LoginPasswordView::TestApi test_api(view_);
   ui::test::EventGenerator* generator = GetEventGenerator();
   // Verify that focus is returned to view after the number insertion.

ash/login/ui/login_pin_view.cc

@@ -474,6 +474,14 @@ LoginPinView::LoginPinView(Style keyboard_style,
     row->AddChildView(submit_button_);
 }
 
+LoginPinView::LoginPinView(Style keyboard_style,
+                           const OnPinKey& on_key,
+                           const OnPinBackspace& on_backspace)
+    : LoginPinView(keyboard_style,
+                   on_key,
+                   on_backspace,
+                   base::RepeatingClosure()) {}
+
 LoginPinView::~LoginPinView() = default;
 
 void LoginPinView::NotifyAccessibilityLocationChanged() {

ash/login/ui/login_pin_view.h

@@ -91,12 +91,19 @@ class ASH_EXPORT LoginPinView : public NonAccessibleView {
   // non-null.
   // |on_backspace| is called when the user wants to erase the most recently
   // tapped key; must be non-null.
-  // |on_submit| is called when the user wants to submit the PIN / password;
-  // pass null in order to hide the submit button.
+  // |on_submit| is called when the user wants to submit the PIN / password.
   LoginPinView(Style keyboard_style,
                const OnPinKey& on_key,
                const OnPinBackspace& on_backspace,
                const OnPinSubmit& on_submit);
+
+  // Creates PIN view without submit button. This is useful when a submit button
+  // is already present in the password view, which is the case when the display
+  // password button feature is disabled.
+  LoginPinView(Style keyboard_style,
+               const OnPinKey& on_key,
+               const OnPinBackspace& on_backspace);
+
   ~LoginPinView() override;
 
   // Notify accessibility that location of rows and LoginPinView changed.

chrome/browser/chromeos/login/login_ui_browsertest.cc

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "ash/public/cpp/login_screen_test_api.h"
+#include "base/test/scoped_feature_list.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/login/lock/screen_locker_tester.h"
 #include "chrome/browser/chromeos/login/login_manager_test.h"
@@ -22,6 +23,7 @@
 #include "chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h"
 #include "chrome/browser/ui/webui/chromeos/login/welcome_screen_handler.h"
 #include "chrome/common/pref_names.h"
+#include "chromeos/constants/chromeos_features.h"
 #include "chromeos/constants/chromeos_pref_names.h"
 #include "components/prefs/pref_service.h"
 #include "components/user_manager/known_user.h"
@@ -165,7 +167,10 @@ IN_PROC_BROWSER_TEST_F(LoginUIEnrolledTest, UserReverseRemoval) {
 
 class DisplayPasswordButtonTest : public LoginManagerTest {
  public:
-  DisplayPasswordButtonTest() : LoginManagerTest() {}
+  DisplayPasswordButtonTest() : LoginManagerTest() {
+    feature_list_.InitWithFeatures(
+        {chromeos::features::kLoginDisplayPasswordButton}, {});
+  }
 
   void LoginAndLock(const LoginManagerMixin::TestUserInfo& test_user) {
     chromeos::WizardController::SkipPostLoginScreensForTesting();
@@ -213,6 +218,9 @@ class DisplayPasswordButtonTest : public LoginManagerTest {
       AccountId::FromUserEmailGaiaId("user@example.com", "22222")};
   UserPolicyMixin user_policy_mixin_{&mixin_host_, managed_user_.account_id};
   LoginManagerMixin login_manager_mixin_{&mixin_host_};
+
+ private:
+  base::test::ScopedFeatureList feature_list_;
 };
 
 // Check if the display password button is shown on the lock screen after having

chromeos/constants/chromeos_features.cc

@@ -253,6 +253,10 @@ const base::Feature kInstantTethering{"InstantTethering",
 const base::Feature kLacrosSupport{"LacrosSupport",
                                    base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables or disables the display password button on login / lock screen.
+const base::Feature kLoginDisplayPasswordButton{
+    "LoginDisplayPasswordButton", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // ChromeOS Media App. https://crbug.com/996088.
 const base::Feature kMediaApp{"MediaApp", base::FEATURE_ENABLED_BY_DEFAULT};
 
@@ -459,6 +463,10 @@ bool IsLacrosSupportEnabled() {
   return base::FeatureList::IsEnabled(kLacrosSupport);
 }
 
+bool IsLoginDisplayPasswordButtonEnabled() {
+  return base::FeatureList::IsEnabled(kLoginDisplayPasswordButton);
+}
+
 bool IsOobeScreensPriorityEnabled() {
   return base::FeatureList::IsEnabled(kOobeScreensPriority);
 }

chromeos/constants/chromeos_features.h

@@ -113,6 +113,8 @@ extern const base::Feature kVirtualKeyboardFloatingDefault;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kInstantTethering;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS) extern const base::Feature kLacrosSupport;
+COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
+extern const base::Feature kLoginDisplayPasswordButton;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS) extern const base::Feature kMediaApp;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kNativeRuleBasedTyping;
@@ -196,6 +198,7 @@ COMPONENT_EXPORT(CHROMEOS_CONSTANTS) bool IsImeSandboxEnabled();
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 bool IsInstantTetheringBackgroundAdvertisingSupported();
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS) bool IsLacrosSupportEnabled();
+COMPONENT_EXPORT(CHROMEOS_CONSTANTS) bool IsLoginDisplayPasswordButtonEnabled();
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS) bool IsOobeScreensPriorityEnabled();
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS) bool IsParentalControlsSettingsEnabled();
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS) bool IsQuickAnswersDogfood();