Create menu view for public account user.

Bug: 809635
Change-Id: Ifd6e73c24c0994f551442ce2d21355829e5454dd
Reviewed-on: https://chromium-review.googlesource.com/1022257
Commit-Queue: Xiaoyin Hu <xiaoyinh@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555866}

ash/BUILD.gn

@@ -334,6 +334,8 @@ component("ash") {
     "login/ui/login_detachable_base_model.h",
     "login/ui/login_expanded_public_account_view.cc",
     "login/ui/login_expanded_public_account_view.h",
+    "login/ui/login_menu_view.cc",
+    "login/ui/login_menu_view.h",
     "login/ui/login_password_view.cc",
     "login/ui/login_password_view.h",
     "login/ui/login_pin_view.cc",

ash/login/ui/lock_contents_view.cc

@@ -572,7 +572,37 @@ void LockContentsView::OnPublicSessionLocalesChanged(
 void LockContentsView::OnPublicSessionKeyboardLayoutsChanged(
     const AccountId& account_id,
     const std::string& locale,
-    const std::vector<mojom::InputMethodItemPtr>& keyboard_layouts) {}
+    const std::vector<mojom::InputMethodItemPtr>& keyboard_layouts) {
+  // Update expanded view because keyboard layouts is user interactive content.
+  // I.e. user selects a language locale and the corresponding keyboard layouts
+  // will be changed.
+  if (expanded_view_->visible() &&
+      expanded_view_->current_user()->basic_user_info->account_id ==
+          account_id) {
+    mojom::LoginUserInfoPtr user_info = expanded_view_->current_user()->Clone();
+    user_info->public_account_info->default_locale = locale;
+    user_info->public_account_info->keyboard_layouts =
+        mojo::Clone(keyboard_layouts);
+    expanded_view_->UpdateForUser(user_info);
+  }
+
+  LoginUserView* user_view = TryToFindUserView(account_id);
+  if (!user_view || !IsPublicAccountUser(user_view->current_user())) {
+    LOG(ERROR) << "Unable to find public account user.";
+    return;
+  }
+
+  mojom::LoginUserInfoPtr user_info = user_view->current_user()->Clone();
+  // Skip updating keyboard layouts if |locale| is not the default locale
+  // of the user. I.e. user changed the default locale in the expanded view,
+  // and it should be handled by expanded view.
+  if (user_info->public_account_info->default_locale != locale)
+    return;
+
+  user_info->public_account_info->keyboard_layouts =
+      mojo::Clone(keyboard_layouts);
+  user_view->UpdateForUser(user_info, false /*animate*/);
+}
 
 void LockContentsView::OnDetachableBasePairingStatusChanged(
     DetachableBasePairingStatus pairing_status) {

ash/login/ui/lock_screen_sanity_unittest.cc

@@ -416,8 +416,7 @@ TEST_F(LockScreenSanityTest, RemoveUser) {
   // dropdown does not result in an interactive/focusable view.
   focus_and_submit(secondary().dropdown());
   EXPECT_TRUE(secondary().menu());
-  EXPECT_FALSE(
-      HasFocusInAnyChildView(secondary().menu()->bubble_view_for_test()));
+  EXPECT_FALSE(HasFocusInAnyChildView(secondary().menu()->bubble_view()));
   // TODO(jdufault): Run submit() and then EXPECT_FALSE(secondary().menu()); to
   // verify that double-enter closes the bubble.
 
@@ -427,7 +426,7 @@ TEST_F(LockScreenSanityTest, RemoveUser) {
   // well as removes the user from the UI.
   focus_and_submit(primary().dropdown());
   EXPECT_TRUE(primary().menu());
-  EXPECT_TRUE(HasFocusInAnyChildView(primary().menu()->bubble_view_for_test()));
+  EXPECT_TRUE(HasFocusInAnyChildView(primary().menu()->bubble_view()));
   EXPECT_CALL(*client, OnRemoveUserWarningShown()).Times(1);
   submit();
   EXPECT_CALL(*client, RemoveUser(users()[0]->basic_user_info->account_id))

ash/login/ui/login_bubble.cc

@@ -13,6 +13,7 @@
 #include "ash/login/ui/lock_screen.h"
 #include "ash/login/ui/lock_window.h"
 #include "ash/login/ui/login_button.h"
+#include "ash/login/ui/login_menu_view.h"
 #include "ash/login/ui/non_accessible_view.h"
 #include "ash/resources/vector_icons/vector_icons.h"
 #include "ash/shell.h"
@@ -404,7 +405,7 @@ void LoginBubble::ShowUserMenu(const base::string16& username,
   bool had_focus = bubble_opener_->HasFocus();
   Show();
   if (had_focus) {
-    // Try to focus the bubble view only if the tooltip was focused.
+    // Try to focus the bubble view only if the bubble opener was focused.
     bubble_view_->RequestFocus();
   }
 }
@@ -419,10 +420,36 @@ void LoginBubble::ShowTooltip(const base::string16& message,
   Show();
 }
 
+void LoginBubble::ShowSelectionMenu(LoginMenuView* menu,
+                                    LoginButton* bubble_opener) {
+  if (bubble_view_)
+    CloseImmediately();
+
+  flags_ = kFlagsNone;
+  bubble_opener_ = bubble_opener;
+  const bool had_focus = bubble_opener_->HasFocus();
+
+  // Transfer the ownership of |menu| to bubble widget.
+  bubble_view_ = menu;
+  Show();
+
+  if (had_focus) {
+    // Try to focus the bubble view only if the bubble opener was focused.
+    bubble_view_->RequestFocus();
+  }
+}
+
 void LoginBubble::Close() {
   ScheduleAnimation(false /*visible*/);
 }
 
+void LoginBubble::CloseImmediately() {
+  DCHECK(bubble_view_);
+  bubble_view_->layer()->GetAnimator()->RemoveObserver(this);
+  bubble_view_->GetWidget()->Close();
+  is_visible_ = false;
+}
+
 bool LoginBubble::IsVisible() {
   return bubble_view_ && bubble_view_->GetWidget()->IsVisible();
 }
@@ -490,13 +517,6 @@ void LoginBubble::Show() {
   bubble_view_->NotifyAccessibilityEvent(ax::mojom::Event::kAlert, true);
 }
 
-void LoginBubble::CloseImmediately() {
-  DCHECK(bubble_view_);
-  bubble_view_->layer()->GetAnimator()->RemoveObserver(this);
-  bubble_view_->GetWidget()->Close();
-  is_visible_ = false;
-}
-
 void LoginBubble::ProcessPressedEvent(const ui::LocatedEvent* event) {
   if (!bubble_view_)
     return;

ash/login/ui/login_bubble.h

@@ -15,6 +15,7 @@
 
 namespace ash {
 class LoginButton;
+class LoginMenuView;
 
 // A wrapper for the bubble view in the login screen.
 // This class observes keyboard events, mouse clicks and touch down events
@@ -58,10 +59,18 @@ class ASH_EXPORT LoginBubble : public views::WidgetObserver,
   // Shows a tooltip.
   void ShowTooltip(const base::string16& message, views::View* anchor_view);
 
+  // Shows a selection menu.
+  void ShowSelectionMenu(LoginMenuView* menu, LoginButton* bubble_opener);
+
   // Schedule animation for closing the bubble.
   // The bubble widget will be closed when the animation is ended.
   void Close();
 
+  // Close the bubble immediately, without scheduling animation.
+  // Used to clean up old bubble widget when a new bubble is going to be
+  // created or it will be called before anchor view is hidden.
+  void CloseImmediately();
+
   // True if the bubble is visible.
   bool IsVisible();
 
@@ -80,17 +89,12 @@ class ASH_EXPORT LoginBubble : public views::WidgetObserver,
   void OnLayerAnimationScheduled(
       ui::LayerAnimationSequence* sequence) override{};
 
-  LoginBaseBubbleView* bubble_view_for_test() { return bubble_view_; }
+  LoginBaseBubbleView* bubble_view() { return bubble_view_; }
 
  private:
   // Show the bubble widget and schedule animation for bubble showing.
   void Show();
 
-  // Close the bubble immediately, without scheduling animation.
-  // Used to clean up old bubble widget when a new bubble is
-  // going to be created.
-  void CloseImmediately();
-
   void ProcessPressedEvent(const ui::LocatedEvent* event);
 
   // Starts show/hide animation.

ash/login/ui/login_bubble_unittest.cc

@@ -7,8 +7,10 @@
 
 #include "ash/login/ui/login_bubble.h"
 #include "ash/login/ui/login_button.h"
+#include "ash/login/ui/login_menu_view.h"
 #include "ash/login/ui/login_test_base.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/bind_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/events/test/event_generator.h"
 #include "ui/views/animation/test/ink_drop_host_view_test_api.h"
@@ -35,6 +37,29 @@ constexpr int kBubbleBottomMarginDp = 18;
 // Non zero size for the bubble anchor view.
 constexpr int kBubbleAnchorViewSizeDp = 100;
 
+std::vector<LoginMenuView::Item> PopulateMenuItems() {
+  std::vector<LoginMenuView::Item> items;
+  // Add one regular item.
+  LoginMenuView::Item item1;
+  item1.title = "Regular Item 1";
+  item1.is_group = false;
+  item1.selected = true;
+  items.push_back(item1);
+
+  // Add one group item.
+  LoginMenuView::Item item2;
+  item2.title = "Group Item 2";
+  item2.is_group = true;
+  items.push_back(item2);
+
+  // Add another regular item.
+  LoginMenuView::Item item3;
+  item3.title = "Regular Item 2";
+  item3.is_group = false;
+  items.push_back(item3);
+  return items;
+}
+
 class LoginBubbleTest : public LoginTestBase {
  protected:
   LoginBubbleTest() = default;
@@ -79,6 +104,12 @@ class LoginBubbleTest : public LoginTestBase {
         std::move(on_remove_show_warning), std::move(on_remove));
   }
 
+  void ShowSelectionMenu(const LoginMenuView::OnSelect& on_select) {
+    LoginMenuView* view =
+        new LoginMenuView(PopulateMenuItems(), container_, on_select);
+    bubble_->ShowSelectionMenu(view, bubble_opener_);
+  }
+
   // Owned by test widget view hierarchy.
   views::View* container_ = nullptr;
   // Owned by test widget view hierarchy.
@@ -99,7 +130,7 @@ TEST_F(LoginBubbleTest, BaseBubbleSettings) {
   bubble_->ShowTooltip(base::string16(), bubble_opener_);
   EXPECT_TRUE(bubble_->IsVisible());
 
-  LoginBaseBubbleView* bubble_view = bubble_->bubble_view_for_test();
+  LoginBaseBubbleView* bubble_view = bubble_->bubble_view();
   EXPECT_EQ(bubble_view->GetDialogButtons(), ui::DIALOG_BUTTON_NONE);
   EXPECT_EQ(bubble_view->width(), kBubbleTotalWidthDp);
   EXPECT_EQ(bubble_view->color(), SK_ColorBLACK);
@@ -151,7 +182,7 @@ TEST_F(LoginBubbleTest, BubbleMouseEventHandling) {
 
   // Verifies that mouse event on the bubble itself won't close the bubble.
   generator.MoveMouseTo(
-      bubble_->bubble_view_for_test()->GetBoundsInScreen().CenterPoint());
+      bubble_->bubble_view()->GetBoundsInScreen().CenterPoint());
   generator.ClickLeftButton();
   EXPECT_TRUE(bubble_->IsVisible());
 
@@ -179,7 +210,7 @@ TEST_F(LoginBubbleTest, BubbleGestureEventHandling) {
 
   // Verifies that gesture event on the bubble itself won't close the bubble.
   generator.GestureTapAt(
-      bubble_->bubble_view_for_test()->GetBoundsInScreen().CenterPoint());
+      bubble_->bubble_view()->GetBoundsInScreen().CenterPoint());
   EXPECT_TRUE(bubble_->IsVisible());
 
   // Verifies that gesture event on the other view will close the bubble.
@@ -229,9 +260,8 @@ TEST_F(LoginBubbleTest, RemoveUserRequiresTwoActivations) {
   EXPECT_TRUE(bubble_->IsVisible());
 
   // Focus the remove user button.
-  views::View* remove_user_button =
-      bubble_->bubble_view_for_test()->GetViewByID(
-          LoginBubble::kUserMenuRemoveUserButtonIdForTest);
+  views::View* remove_user_button = bubble_->bubble_view()->GetViewByID(
+      LoginBubble::kUserMenuRemoveUserButtonIdForTest);
   remove_user_button->RequestFocus();
   EXPECT_TRUE(remove_user_button->HasFocus());
 
@@ -276,7 +306,7 @@ TEST_F(LoginBubbleTest, ErrorBubbleMouseEventHandling) {
 
   // Verifies that mouse event on the bubble itself won't close the bubble.
   generator.MoveMouseTo(
-      bubble_->bubble_view_for_test()->GetBoundsInScreen().CenterPoint());
+      bubble_->bubble_view()->GetBoundsInScreen().CenterPoint());
   generator.ClickLeftButton();
   EXPECT_TRUE(bubble_->IsVisible());
 
@@ -296,7 +326,7 @@ TEST_F(LoginBubbleTest, ErrorBubbleGestureEventHandling) {
 
   // Verifies that gesture event on the bubble itself won't close the bubble.
   generator.GestureTapAt(
-      bubble_->bubble_view_for_test()->GetBoundsInScreen().CenterPoint());
+      bubble_->bubble_view()->GetBoundsInScreen().CenterPoint());
   EXPECT_TRUE(bubble_->IsVisible());
 
   // Verifies that gesture event on the other view will close the bubble.
@@ -315,7 +345,7 @@ TEST_F(LoginBubbleTest, PersistentErrorBubbleEventHandling) {
 
   // Verifies that mouse event on the bubble itself won't close the bubble.
   generator.MoveMouseTo(
-      bubble_->bubble_view_for_test()->GetBoundsInScreen().CenterPoint());
+      bubble_->bubble_view()->GetBoundsInScreen().CenterPoint());
   generator.ClickLeftButton();
   EXPECT_TRUE(bubble_->IsVisible());
 
@@ -326,7 +356,7 @@ TEST_F(LoginBubbleTest, PersistentErrorBubbleEventHandling) {
 
   // Verifies that gesture event on the bubble itself won't close the bubble.
   generator.GestureTapAt(
-      bubble_->bubble_view_for_test()->GetBoundsInScreen().CenterPoint());
+      bubble_->bubble_view()->GetBoundsInScreen().CenterPoint());
   EXPECT_TRUE(bubble_->IsVisible());
 
   // Verifies that gesture event on the other view won't close the bubble.
@@ -343,4 +373,57 @@ TEST_F(LoginBubbleTest, PersistentErrorBubbleEventHandling) {
   EXPECT_FALSE(bubble_->IsVisible());
 }
 
+TEST_F(LoginBubbleTest, TestShowSelectionMenu) {
+  ui::test::EventGenerator& generator = GetEventGenerator();
+
+  EXPECT_FALSE(bubble_->IsVisible());
+  LoginMenuView::Item selected_item;
+  bool selected = false;
+  ShowSelectionMenu(base::BindLambdaForTesting([&](LoginMenuView::Item item) {
+    selected_item = item;
+    selected = true;
+  }));
+  EXPECT_TRUE(bubble_->IsVisible());
+
+  // Verifies that regular item 1 is selectable.
+  LoginMenuView* menu_view =
+      static_cast<LoginMenuView*>(bubble_->bubble_view());
+  LoginMenuView::TestApi test_api1(menu_view);
+  EXPECT_TRUE(test_api1.contents()->child_at(0)->HasFocus());
+  generator.PressKey(ui::KeyboardCode::VKEY_RETURN, 0 /*flag*/);
+  EXPECT_FALSE(bubble_->IsVisible());
+  EXPECT_EQ(selected_item.title, "Regular Item 1");
+  EXPECT_TRUE(selected);
+
+  // Verfies that group item 2 is not selectable.
+  selected = false;
+  ShowSelectionMenu(base::BindLambdaForTesting([&](LoginMenuView::Item item) {
+    selected_item = item;
+    selected = true;
+  }));
+  EXPECT_TRUE(bubble_->IsVisible());
+  menu_view = static_cast<LoginMenuView*>(bubble_->bubble_view());
+  LoginMenuView::TestApi test_api2(menu_view);
+  test_api2.contents()->child_at(1)->RequestFocus();
+  generator.PressKey(ui::KeyboardCode::VKEY_RETURN, 0 /*flag*/);
+  EXPECT_TRUE(bubble_->IsVisible());
+  EXPECT_FALSE(selected);
+
+  // Verifies up/down arrow key can navigate menu entries.
+  generator.PressKey(ui::KeyboardCode::VKEY_UP, 0 /*flag*/);
+  EXPECT_TRUE(test_api2.contents()->child_at(0)->HasFocus());
+  generator.PressKey(ui::KeyboardCode::VKEY_UP, 0 /*flag*/);
+  EXPECT_TRUE(test_api2.contents()->child_at(0)->HasFocus());
+
+  generator.PressKey(ui::KeyboardCode::VKEY_DOWN, 0 /*flag*/);
+  // Group item is skipped in up/down key navigation.
+  EXPECT_TRUE(test_api2.contents()->child_at(2)->HasFocus());
+  generator.PressKey(ui::KeyboardCode::VKEY_DOWN, 0 /*flag*/);
+  EXPECT_TRUE(test_api2.contents()->child_at(2)->HasFocus());
+  EXPECT_TRUE(bubble_->IsVisible());
+
+  bubble_->Close();
+  EXPECT_FALSE(bubble_->IsVisible());
+}
+
 }  // namespace ash

ash/login/ui/login_expanded_public_account_view.h

@@ -43,6 +43,7 @@ class ASH_EXPORT LoginExpandedPublicAccountView : public NonAccessibleView {
   void ProcessPressedEvent(const ui::LocatedEvent* event);
   void UpdateForUser(const mojom::LoginUserInfoPtr& user);
   const mojom::LoginUserInfoPtr& current_user() const;
+  void Hide();
 
   // views::View:
   void OnPaint(gfx::Canvas* canvas) override;

ash/login/ui/login_menu_view.cc

+// Copyright 2018 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.
+
+#include "ash/login/ui/login_menu_view.h"
+
+#include "ash/login/ui/hover_notifier.h"
+#include "ash/login/ui/non_accessible_view.h"
+#include "base/strings/utf_string_conversions.h"
+#include "ui/views/controls/button/button.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/controls/scroll_view.h"
+#include "ui/views/controls/scrollbar/overlay_scroll_bar.h"
+#include "ui/views/layout/box_layout.h"
+
+namespace ash {
+
+constexpr int kMenuItemWidthDp = 178;
+constexpr int kMenuItemHeightDp = 28;
+constexpr int kRegularMenuItemLeftPaddingDp = 2;
+constexpr int kGroupMenuItemLeftPaddingDp = 10;
+constexpr int kNonEmptyHeight = 1;
+
+namespace {
+
+constexpr SkColor kMenuBackgroundColor = SkColorSetRGB(0x3C, 0x40, 0x43);
+
+class MenuItemView : public views::Button, public views::ButtonListener {
+ public:
+  MenuItemView(const LoginMenuView::Item& item,
+               const LoginMenuView::OnHighLight& on_highlight)
+      : views::Button(this), item_(item), on_highlight_(on_highlight) {
+    SetFocusBehavior(FocusBehavior::ALWAYS);
+    SetLayoutManager(
+        std::make_unique<views::BoxLayout>(views::BoxLayout::kHorizontal));
+    SetPreferredSize(gfx::Size(kMenuItemWidthDp, kMenuItemHeightDp));
+
+    auto* spacing = new NonAccessibleView();
+    spacing->SetPreferredSize(gfx::Size(item.is_group
+                                            ? kRegularMenuItemLeftPaddingDp
+                                            : kGroupMenuItemLeftPaddingDp,
+                                        kNonEmptyHeight));
+    AddChildView(spacing);
+
+    views::Label* label = new views::Label(base::UTF8ToUTF16(item.title));
+    label->SetEnabledColor(SK_ColorWHITE);
+    label->SetSubpixelRenderingEnabled(false);
+    label->SetAutoColorReadabilityEnabled(false);
+    label->SetHorizontalAlignment(gfx::ALIGN_LEFT);
+    AddChildView(label);
+
+    if (item.selected)
+      SetBackground(views::CreateSolidBackground(SK_ColorGRAY));
+
+    hover_notifier_ = std::make_unique<HoverNotifier>(
+        this,
+        base::BindRepeating(&MenuItemView::OnHover, base::Unretained(this)));
+  }
+
+  ~MenuItemView() override = default;
+
+  // views::View:
+  int GetHeightForWidth(int w) const override {
+    // Make row height fixed avoiding layout manager adjustments.
+    return GetPreferredSize().height();
+  }
+
+  // views::ButtonListener:
+  void ButtonPressed(views::Button* sender, const ui::Event& event) override {
+    DCHECK(sender == this);
+    if (item_.is_group)
+      return;
+
+    on_highlight_.Run(true /*by_selection*/);
+    GetWidget()->Close();
+  }
+
+  void OnHover(bool has_hover) {
+    if (has_hover && !item_.is_group)
+      RequestFocus();
+  }
+
+  void OnFocus() override {
+    ScrollViewToVisible();
+    on_highlight_.Run(false /*by_selection*/);
+  }
+
+  const LoginMenuView::Item& item() const { return item_; }
+
+ private:
+  const LoginMenuView::Item item_;
+  const LoginMenuView::OnHighLight on_highlight_;
+  std::unique_ptr<HoverNotifier> hover_notifier_;
+
+  DISALLOW_COPY_AND_ASSIGN(MenuItemView);
+};
+
+class LoginScrollBar : public views::OverlayScrollBar {
+ public:
+  LoginScrollBar() : OverlayScrollBar(false) {}
+
+  // OverlayScrollBar:
+  bool OnKeyPressed(const ui::KeyEvent& event) override {
+    // Let LoginMenuView to handle up/down keypress.
+    return false;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(LoginScrollBar);
+};
+
+}  // namespace
+
+LoginMenuView::TestApi::TestApi(LoginMenuView* view) : view_(view) {}
+
+LoginMenuView::TestApi::~TestApi() = default;
+
+views::View* LoginMenuView::TestApi::contents() const {
+  return view_->contents_;
+}
+
+LoginMenuView::Item::Item() = default;
+
+LoginMenuView::LoginMenuView(const std::vector<Item>& items,
+                             views::View* anchor_view,
+                             const OnSelect& on_select)
+    : LoginBaseBubbleView(anchor_view), on_select_(on_select) {
+  set_can_activate(true);
+  set_margins(gfx::Insets());
+  set_color(kMenuBackgroundColor);
+  SetFocusBehavior(views::View::FocusBehavior::ALWAYS);
+
+  scroller_ = new views::ScrollView();
+  scroller_->SetBackgroundColor(SK_ColorTRANSPARENT);
+  scroller_->set_draw_overflow_indicator(false);
+  scroller_->ClipHeightTo(kMenuItemHeightDp, kMenuItemHeightDp * 5);
+  AddChildView(scroller_);
+
+  views::BoxLayout* box_layout = SetLayoutManager(
+      std::make_unique<views::BoxLayout>(views::BoxLayout::kVertical));
+  box_layout->SetFlexForView(scroller_, 1);
+
+  contents_ = new NonAccessibleView();
+  views::BoxLayout* layout = contents_->SetLayoutManager(
+      std::make_unique<views::BoxLayout>(views::BoxLayout::kVertical));
+  layout->SetDefaultFlex(1);
+  layout->set_minimum_cross_axis_size(kMenuItemWidthDp);
+  layout->set_main_axis_alignment(
+      views::BoxLayout::MainAxisAlignment::MAIN_AXIS_ALIGNMENT_CENTER);
+
+  for (size_t i = 0; i < items.size(); i++) {
+    const Item& item = items[i];
+    contents_->AddChildView(new MenuItemView(
+        item, base::BindRepeating(&LoginMenuView::OnHighLightChange,
+                                  base::Unretained(this), i)));
+
+    if (item.selected)
+      selected_index_ = i;
+  }
+  scroller_->SetContents(contents_);
+  scroller_->SetVerticalScrollBar(new LoginScrollBar());
+}
+
+LoginMenuView::~LoginMenuView() = default;
+
+void LoginMenuView::OnHighLightChange(int item_index, bool by_selection) {
+  selected_index_ = item_index;
+  views::View* highlight_item = contents_->child_at(item_index);
+  for (views::View* child : contents_->GetChildrenInZOrder()) {
+    child->SetBackground(views::CreateSolidBackground(
+        child == highlight_item ? SK_ColorGRAY : SK_ColorTRANSPARENT));
+  }
+
+  if (by_selection) {
+    MenuItemView* menu_view = static_cast<MenuItemView*>(highlight_item);
+    on_select_.Run(menu_view->item());
+  }
+  contents_->SchedulePaint();
+}
+
+int LoginMenuView::FindNextItem(bool reverse) {
+  int delta = reverse ? -1 : 1;
+  int current_index = selected_index_ + delta;
+  while (current_index >= 0 && current_index < contents_->child_count()) {
+    MenuItemView* menu_view =
+        static_cast<MenuItemView*>(contents_->child_at(current_index));
+    if (!menu_view->item().is_group)
+      break;
+    current_index += delta;
+  }
+
+  if (current_index < 0 || current_index == contents_->child_count())
+    return selected_index_;
+  return current_index;
+}
+
+void LoginMenuView::OnFocus() {
+  // Forward the focus to the selected child view.
+  contents_->child_at(selected_index_)->RequestFocus();
+}
+
+bool LoginMenuView::OnKeyPressed(const ui::KeyEvent& event) {
+  const ui::KeyboardCode key = event.key_code();
+  if (key == ui::VKEY_UP || key == ui::VKEY_DOWN) {
+    contents_->child_at(FindNextItem(key == ui::VKEY_UP))->RequestFocus();
+    return true;
+  }
+
+  return false;
+}
+
+void LoginMenuView::VisibilityChanged(View* starting_from, bool is_visible) {
+  if (is_visible)
+    contents_->child_at(selected_index_)->RequestFocus();
+}
+
+}  // namespace ash

ash/login/ui/login_menu_view.h

+// Copyright 2018 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.
+
+#ifndef ASH_LOGIN_UI_LOGIN_MENU_VIEW_H_
+#define ASH_LOGIN_UI_LOGIN_MENU_VIEW_H_
+
+#include "ash/ash_export.h"
+#include "ash/login/ui/login_base_bubble_view.h"
+#include "base/callback.h"
+#include "ui/views/view.h"
+
+namespace ash {
+
+// Implements a menu view for login screen.
+// This is used instead of views::Combobox because we want a more customisable
+// view for the menu items to support some sepcific styles like nested menu
+// entries which have different left margin (less than regular items) and are
+// not selectable. views::Combobox uses views::MenuItemView which is not very
+// straightforward to customize.
+class ASH_EXPORT LoginMenuView : public LoginBaseBubbleView {
+ public:
+  // TestApi is used for tests to get internal implementation details.
+  class ASH_EXPORT TestApi {
+   public:
+    explicit TestApi(LoginMenuView* view);
+    ~TestApi();
+
+    views::View* contents() const;
+
+   private:
+    LoginMenuView* const view_;
+  };
+
+  struct Item {
+    Item();
+
+    std::string title;
+    std::string value;
+    bool is_group = false;
+    bool selected = false;
+  };
+
+  using OnSelect = base::RepeatingCallback<void(Item item)>;
+  using OnHighLight = base::RepeatingCallback<void(bool by_selection)>;
+
+  LoginMenuView(const std::vector<Item>& items,
+                views::View* anchor_view,
+                const OnSelect& on_select);
+  ~LoginMenuView() override;
+
+  void OnHighLightChange(int item_index, bool by_selection);
+  int FindNextItem(bool reverse);
+
+  // views::View:
+  void OnFocus() override;
+  bool OnKeyPressed(const ui::KeyEvent& event) override;
+  void VisibilityChanged(View* starting_from, bool is_visible) override;
+
+ private:
+  // Owned by this class.
+  views::ScrollView* scroller_ = nullptr;
+
+  // Owned by ScrollView.
+  views::View* contents_ = nullptr;
+
+  const OnSelect on_select_;
+  int selected_index_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(LoginMenuView);
+};
+
+}  // namespace ash
+
+#endif  // ASH_LOGIN_UI_LOGIN_MENU_VIEW_H_