[a11y] Add mouse keys to the status tray.

This adds a button in the status tray that can be used to turn mouse keys on/off.  The logic to toggle mouse keys is not added in this CL and will be added in a follow-up.

https://screenshot.googleplex.com/4Ykomm4SvXcuTAZ.png

BUG=b:259372916
TEST=ash_unittests --gtest_filter=MouseKeysTrayTest.*

Change-Id: Iedccbdfc5535571da7e39248129a00222bbe50f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5713956
Reviewed-by: Akihiro Ota <akihiroota@chromium.org>
Commit-Queue: Tzarial <zork@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1354358}

ash/BUILD.gn

@@ -1585,6 +1585,8 @@ component("ash") {
     "system/accessibility/floating_menu_button.h",
     "system/accessibility/floating_menu_utils.cc",
     "system/accessibility/floating_menu_utils.h",
+    "system/accessibility/mouse_keys/mouse_keys_tray.cc",
+    "system/accessibility/mouse_keys/mouse_keys_tray.h",
     "system/accessibility/select_to_speak/select_to_speak_constants.h",
     "system/accessibility/select_to_speak/select_to_speak_menu_bubble_controller.cc",
     "system/accessibility/select_to_speak/select_to_speak_menu_bubble_controller.h",
@@ -4032,6 +4034,7 @@ test("ash_unittests") {
     "system/accessibility/dictation_bubble_controller_unittest.cc",
     "system/accessibility/dictation_button_tray_unittest.cc",
     "system/accessibility/floating_accessibility_controller_unittest.cc",
+    "system/accessibility/mouse_keys/mouse_keys_tray_unittest.cc",
     "system/accessibility/select_to_speak/select_to_speak_menu_bubble_controller_unittest.cc",
     "system/accessibility/select_to_speak/select_to_speak_speed_bubble_controller_unittest.cc",
     "system/accessibility/select_to_speak/select_to_speak_tray_unittest.cc",

ash/ash_strings.grd

@@ -1236,6 +1236,9 @@ Style notes:
     system tray to toggle on/off spoken feedback feature.">
         ChromeVox (spoken feedback)
       </message>
+      <message name="IDS_ASH_STATUS_TRAY_ACCESSIBILITY_MOUSE_KEYS" desc="The label used in the accessibility menu of the system tray to pause/resume the mouse keys feature.">
+        Mouse keys
+      </message>
       <message name="IDS_ASH_STATUS_TRAY_ACCESSIBILITY_SELECT_TO_SPEAK" desc="The label used in the accessibility menu of the system tray to toggle on/off the select-to-speak feature.">
         Select-to-speak
       </message>
@@ -4062,6 +4065,9 @@ No devices connected.
       <message name="IDS_ASH_IME_MENU_ACCESSIBLE_NAME" desc="The accessible text for opt-in IME menu icon in status tray.">
         IME menu button
       </message>
+      <message name="IDS_ASH_MOUSE_KEYS_TRAY_ACCESSIBLE_NAME" desc="The accessible text for the mouse keys menu icon in the status tray.">
+        Mouse keys button
+      </message>
       <message name="IDS_ASH_SELECT_TO_SPEAK_TRAY_ACCESSIBLE_NAME" desc="The accessible text for the select-to-speak menu icon in the status tray.">
         Select-to-speak button
       </message>

ash/ash_strings_grd/IDS_ASH_MOUSE_KEYS_TRAY_ACCESSIBLE_NAME.png.sha1

@@ -0,0 +1 @@
+5de6b877847d89bf6bf59640fcdde02e5be3d7d3

ash/ash_strings_grd/IDS_ASH_STATUS_TRAY_ACCESSIBILITY_MOUSE_KEYS.png.sha1

@@ -0,0 +1 @@
+5de6b877847d89bf6bf59640fcdde02e5be3d7d3

ash/constants/tray_background_view_catalog.h

@@ -38,7 +38,8 @@ enum class TrayBackgroundViewCatalogName {
   kVideoConferenceTray = 22,
   kFocusMode = 23,
   kPodsOverflow = 24,
-  kMaxValue = kPodsOverflow,
+  kMouseKeysStatusArea = 25,
+  kMaxValue = kMouseKeysStatusArea,
 };
 
 }  // namespace ash

ash/resources/vector_icons/BUILD.gn

@@ -555,6 +555,7 @@ aggregate_vector_icons("ash_vector_icons") {
     "system_tray_cast.icon",
     "system_tray_do_not_disturb.icon",
     "system_tray_managed.icon",
+    "system_tray_mouse_keys.icon",
     "system_tray_notification_counter_plus.icon",
     "system_tray_recording.icon",
     "system_tray_rotation_lock_auto.icon",

ash/resources/vector_icons/system_tray_mouse_keys.icon

@@ -0,0 +1,85 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+CANVAS_DIMENSIONS, 20,
+MOVE_TO, 3.5f, 3,
+CUBIC_TO, 2.95f, 3, 2.5f, 3.45f, 2.5f, 4,
+V_LINE_TO, 6,
+CUBIC_TO, 2.5f, 6.55f, 2.95f, 7, 3.5f, 7,
+H_LINE_TO, 5.5f,
+CUBIC_TO, 6.05f, 7, 6.5f, 6.55f, 6.5f, 6,
+V_LINE_TO, 4,
+CUBIC_TO, 6.5f, 3.45f, 6.05f, 3, 5.5f, 3,
+H_LINE_TO, 3.5f,
+CLOSE,
+MOVE_TO, 8.5f, 3,
+CUBIC_TO, 7.95f, 3, 7.5f, 3.45f, 7.5f, 4,
+V_LINE_TO, 6,
+CUBIC_TO, 7.5f, 6.36f, 7.69f, 6.68f, 7.98f, 6.86f,
+CUBIC_TO, 8.65f, 5.46f, 9.94f, 4.42f, 11.5f, 4.1f,
+V_LINE_TO, 4,
+CUBIC_TO, 11.5f, 3.45f, 11.05f, 3, 10.5f, 3,
+H_LINE_TO, 8.5f,
+CLOSE,
+MOVE_TO, 16.5f, 4,
+V_LINE_TO, 5,
+CUBIC_TO, 15.66f, 4.37f, 14.63f, 4, 13.5f, 4,
+H_LINE_TO, 12.5f,
+CUBIC_TO, 12.5f, 3.45f, 12.95f, 3, 13.5f, 3,
+H_LINE_TO, 15.5f,
+CUBIC_TO, 16.05f, 3, 16.5f, 3.45f, 16.5f, 4,
+CLOSE,
+MOVE_TO, 3.5f, 8,
+CUBIC_TO, 2.95f, 8, 2.5f, 8.45f, 2.5f, 9,
+V_LINE_TO, 11,
+CUBIC_TO, 2.5f, 11.55f, 2.95f, 12, 3.5f, 12,
+H_LINE_TO, 5.5f,
+CUBIC_TO, 6.05f, 12, 6.5f, 11.55f, 6.5f, 11,
+V_LINE_TO, 9,
+CUBIC_TO, 6.5f, 8.45f, 6.05f, 8, 5.5f, 8,
+H_LINE_TO, 3.5f,
+CLOSE,
+MOVE_TO, 2.5f, 14,
+CUBIC_TO, 2.5f, 13.45f, 2.95f, 13, 3.5f, 13,
+H_LINE_TO, 5.5f,
+CUBIC_TO, 6.05f, 13, 6.5f, 13.45f, 6.5f, 14,
+V_LINE_TO, 16,
+CUBIC_TO, 6.5f, 16.55f, 6.05f, 17, 5.5f, 17,
+H_LINE_TO, 3.5f,
+CUBIC_TO, 2.95f, 17, 2.5f, 16.55f, 2.5f, 16,
+V_LINE_TO, 14,
+CLOSE,
+MOVE_TO, 15.17f, 14.6f,
+CUBIC_TO, 14.6f, 15.17f, 13.9f, 15.46f, 13.08f, 15.46f,
+CUBIC_TO, 12.28f, 15.46f, 11.58f, 15.17f, 11, 14.6f,
+CUBIC_TO, 10.43f, 14.02f, 10.15f, 13.33f, 10.15f, 12.52f,
+V_LINE_TO, 11.69f,
+H_LINE_TO, 16.02f,
+V_LINE_TO, 12.52f,
+CUBIC_TO, 16.02f, 13.33f, 15.74f, 14.02f, 15.17f, 14.6f,
+CLOSE,
+MOVE_TO, 12.27f, 10.06f,
+H_LINE_TO, 10.19f,
+CUBIC_TO, 10.27f, 9.48f, 10.5f, 8.98f, 10.88f, 8.56f,
+CUBIC_TO, 11.25f, 8.15f, 11.72f, 7.85f, 12.27f, 7.69f,
+V_LINE_TO, 10.06f,
+CLOSE,
+MOVE_TO, 15.98f, 10.06f,
+H_LINE_TO, 13.9f,
+V_LINE_TO, 7.69f,
+CUBIC_TO, 14.45f, 7.85f, 14.91f, 8.15f, 15.27f, 8.56f,
+CUBIC_TO, 15.65f, 8.98f, 15.88f, 9.48f, 15.98f, 10.06f,
+CLOSE,
+MOVE_TO, 9.81f, 15.79f,
+CUBIC_TO, 10.7f, 16.67f, 11.79f, 17.1f, 13.08f, 17.1f,
+CUBIC_TO, 14.38f, 17.1f, 15.46f, 16.67f, 16.33f, 15.79f,
+CUBIC_TO, 17.22f, 14.9f, 17.67f, 13.81f, 17.67f, 12.52f,
+V_LINE_TO, 10.58f,
+CUBIC_TO, 17.67f, 9.29f, 17.22f, 8.21f, 16.33f, 7.33f,
+CUBIC_TO, 15.46f, 6.45f, 14.38f, 6, 13.08f, 6,
+CUBIC_TO, 11.79f, 6, 10.7f, 6.45f, 9.81f, 7.33f,
+CUBIC_TO, 8.94f, 8.21f, 8.5f, 9.29f, 8.5f, 10.58f,
+V_LINE_TO, 12.52f,
+CUBIC_TO, 8.5f, 13.81f, 8.94f, 14.9f, 9.81f, 15.79f,
+CLOSE

ash/system/accessibility/mouse_keys/mouse_keys_tray.cc

@@ -0,0 +1,113 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ash/system/accessibility/mouse_keys/mouse_keys_tray.h"
+
+#include "ash/accessibility/accessibility_controller.h"
+#include "ash/constants/tray_background_view_catalog.h"
+#include "ash/resources/vector_icons/vector_icons.h"
+#include "ash/session/session_controller_impl.h"
+#include "ash/shelf/shelf.h"
+#include "ash/shell.h"
+#include "ash/strings/grit/ash_strings.h"
+#include "ash/style/ash_color_id.h"
+#include "ash/system/tray/tray_constants.h"
+#include "ash/system/tray/tray_container.h"
+#include "ash/system/tray/tray_utils.h"
+#include "ui/accessibility/accessibility_features.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/metadata/metadata_impl_macros.h"
+#include "ui/base/models/image_model.h"
+#include "ui/color/color_id.h"
+#include "ui/gfx/paint_vector_icon.h"
+#include "ui/views/border.h"
+#include "ui/views/controls/image_view.h"
+
+namespace ash {
+
+namespace {
+
+// Arbitrary ID for the icon.
+const int kMouseKeysTrayIconID = 11;
+
+ui::ImageModel GetMouseKeysIcon() {
+  return ui::ImageModel::FromVectorIcon(
+      kSystemTrayMouseKeysIcon,
+      static_cast<ui::ColorId>(cros_tokens::kCrosSysOnSurface));
+}
+
+}  // namespace
+
+MouseKeysTray::MouseKeysTray(Shelf* shelf,
+                             TrayBackgroundViewCatalogName catalog_name)
+    : TrayBackgroundView(shelf, catalog_name) {
+  const ui::ImageModel image = GetMouseKeysIcon();
+  const int vertical_padding = (kTrayItemSize - image.Size().height()) / 2;
+  const int horizontal_padding = (kTrayItemSize - image.Size().width()) / 2;
+  tray_container()->AddChildView(
+      views::Builder<views::ImageView>()
+          .SetID(kMouseKeysTrayIconID)
+          .SetTooltipText(l10n_util::GetStringUTF16(
+              IDS_ASH_STATUS_TRAY_ACCESSIBILITY_MOUSE_KEYS))
+          .SetImage(image)
+          .SetBorder(views::CreateEmptyBorder(
+              gfx::Insets::VH(vertical_padding, horizontal_padding)))
+          .Build());
+
+  // Observe the accessibility controller state changes to know when mouse keys
+  // state is updated or when it is disabled/enabled.
+  Shell::Get()->accessibility_controller()->AddObserver(this);
+}
+
+MouseKeysTray::~MouseKeysTray() {
+  // This may be called during shutdown in which case some of the
+  // ash objects may already be destroyed.
+  auto* shell = Shell::Get();
+  if (!shell) {
+    return;
+  }
+  auto* accessibility_controller = shell->accessibility_controller();
+  if (accessibility_controller) {
+    accessibility_controller->RemoveObserver(this);
+  }
+}
+
+void MouseKeysTray::Initialize() {
+  TrayBackgroundView::Initialize();
+  OnAccessibilityStatusChanged();
+  HandleLocaleChange();
+}
+
+std::u16string MouseKeysTray::GetAccessibleNameForTray() {
+  return l10n_util::GetStringUTF16(IDS_ASH_MOUSE_KEYS_TRAY_ACCESSIBLE_NAME);
+}
+
+void MouseKeysTray::HandleLocaleChange() {
+  GetIcon()->SetTooltipText(
+      l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_ACCESSIBILITY_MOUSE_KEYS));
+}
+
+void MouseKeysTray::UpdateTrayItemColor(bool is_active) {
+  SetIsActive(is_active);
+}
+
+void MouseKeysTray::OnAccessibilityStatusChanged() {
+  auto* accessibility_controller = Shell::Get()->accessibility_controller();
+  SetVisiblePreferred(::features::IsAccessibilityMouseKeysEnabled() &&
+                      accessibility_controller->mouse_keys().enabled());
+}
+
+void MouseKeysTray::OnSessionStateChanged(session_manager::SessionState state) {
+  GetIcon()->SetImage(GetMouseKeysIcon());
+}
+
+views::ImageView* MouseKeysTray::GetIcon() {
+  return static_cast<views::ImageView*>(
+      tray_container()->GetViewByID(kMouseKeysTrayIconID));
+}
+
+BEGIN_METADATA(MouseKeysTray);
+END_METADATA
+
+}  // namespace ash

ash/system/accessibility/mouse_keys/mouse_keys_tray.h

@@ -0,0 +1,63 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_SYSTEM_ACCESSIBILITY_MOUSE_KEYS_MOUSE_KEYS_TRAY_H_
+#define ASH_SYSTEM_ACCESSIBILITY_MOUSE_KEYS_MOUSE_KEYS_TRAY_H_
+
+#include <string>
+
+#include "ash/accessibility/accessibility_observer.h"
+#include "ash/ash_export.h"
+#include "ash/constants/tray_background_view_catalog.h"
+#include "ash/public/cpp/session/session_observer.h"
+#include "ash/system/tray/tray_background_view.h"
+#include "base/memory/raw_ptr.h"
+#include "ui/base/metadata/metadata_header_macros.h"
+
+namespace views {
+class ImageView;
+}  // namespace views
+
+namespace ash {
+
+class Shelf;
+
+// A button in the tray that lets users start/stop mouse keys.
+class ASH_EXPORT MouseKeysTray : public TrayBackgroundView,
+                                 public AccessibilityObserver,
+                                 public SessionObserver {
+  METADATA_HEADER(MouseKeysTray, TrayBackgroundView)
+
+ public:
+  MouseKeysTray(Shelf* shelf, TrayBackgroundViewCatalogName catalog_name);
+  MouseKeysTray(const MouseKeysTray&) = delete;
+  MouseKeysTray& operator=(const MouseKeysTray&) = delete;
+  ~MouseKeysTray() override;
+
+  // TrayBackgroundView:
+  void Initialize() override;
+  std::u16string GetAccessibleNameForTray() override;
+  void HandleLocaleChange() override;
+  void HideBubbleWithView(const TrayBubbleView* bubble_view) override {}
+  void HideBubble(const TrayBubbleView* bubble_view) override {}
+  void ClickedOutsideBubble(const ui::LocatedEvent& event) override {}
+  void UpdateTrayItemColor(bool is_active) override;
+
+  // AccessibilityObserver:
+  void OnAccessibilityStatusChanged() override;
+
+  // SessionObserver:
+  void OnSessionStateChanged(session_manager::SessionState state) override;
+
+ private:
+  friend class MouseKeysTrayTest;
+
+  views::ImageView* GetIcon();
+
+  ScopedSessionObserver session_observer_{this};
+};
+
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_ACCESSIBILITY_MOUSE_KEYS_MOUSE_KEYS_TRAY_H_

ash/system/accessibility/mouse_keys/mouse_keys_tray_unittest.cc

@@ -0,0 +1,88 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ash/system/accessibility/mouse_keys/mouse_keys_tray.h"
+
+#include "ash/accessibility/accessibility_controller.h"
+#include "ash/shell.h"
+#include "ash/system/status_area_widget.h"
+#include "ash/system/status_area_widget_test_helper.h"
+#include "ash/test/ash_test_base.h"
+#include "base/test/scoped_feature_list.h"
+#include "ui/accessibility/accessibility_features.h"
+#include "ui/events/base_event_utils.h"
+
+namespace ash {
+
+namespace {
+
+MouseKeysTray* GetTray() {
+  return StatusAreaWidgetTestHelper::GetStatusAreaWidget()->mouse_keys_tray();
+}
+
+// Returns true if the Mouse keys tray is visible.
+bool IsVisible() {
+  return GetTray()->GetVisible();
+}
+
+}  // namespace
+
+class MouseKeysTrayTest : public AshTestBase {
+ public:
+  MouseKeysTrayTest() = default;
+
+  MouseKeysTrayTest(const MouseKeysTrayTest&) = delete;
+  MouseKeysTrayTest& operator=(const MouseKeysTrayTest&) = delete;
+
+  ~MouseKeysTrayTest() override = default;
+
+  void SetUp() override {
+    scoped_feature_list_.InitAndEnableFeature(
+        ::features::kAccessibilityMouseKeys);
+    AshTestBase::SetUp();
+    Shell::Get()->accessibility_controller()->mouse_keys().SetEnabled(true);
+
+    EXPECT_TRUE(GetImageView());
+    EXPECT_TRUE(IsVisible());
+  }
+
+ private:
+  // Gets the current tray image view.
+  views::ImageView* GetImageView() { return GetTray()->GetIcon(); }
+
+  base::test::ScopedFeatureList scoped_feature_list_;
+};
+
+// Tests the icon disappears when mouse keys is disabled and re-appears
+// when it is enabled.
+TEST_F(MouseKeysTrayTest, ShowsAndHidesWithMouseKeysEnabled) {
+  Shell::Get()->accessibility_controller()->mouse_keys().SetEnabled(false);
+  EXPECT_FALSE(IsVisible());
+  Shell::Get()->accessibility_controller()->mouse_keys().SetEnabled(true);
+  EXPECT_TRUE(IsVisible());
+}
+
+// Trivial test to increase coverage of mouse_keys_tray.h. The
+// MouseKeysTray does not have a bubble, so these are empty functions.
+// Without this test, coverage of mouse_keys_tray.h is 0%.
+TEST_F(MouseKeysTrayTest, OverriddenFunctionsDoNothing) {
+  GetTray()->HideBubbleWithView(nullptr);
+  const ui::MouseEvent event(ui::EventType::kMousePressed, gfx::Point(),
+                             gfx::Point(), ui::EventTimeForNow(), 0, 0);
+  GetTray()->ClickedOutsideBubble(event);
+}
+
+using MouseKeysTrayTestFeatureDisabled = AshTestBase;
+
+TEST_F(MouseKeysTrayTestFeatureDisabled, TrayHidden) {
+  Shell::Get()->accessibility_controller()->mouse_keys().SetEnabled(true);
+  // Tray should exist even when the feature is disabled.
+  EXPECT_TRUE(GetTray());
+  // However, it shouldn't be visible.
+  EXPECT_FALSE(IsVisible());
+  Shell::Get()->accessibility_controller()->mouse_keys().SetEnabled(false);
+  EXPECT_FALSE(IsVisible());
+}
+
+}  // namespace ash

ash/system/status_area_widget.cc

@@ -21,6 +21,7 @@
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/system/accessibility/dictation_button_tray.h"
+#include "ash/system/accessibility/mouse_keys/mouse_keys_tray.h"
 #include "ash/system/accessibility/select_to_speak/select_to_speak_tray.h"
 #include "ash/system/eche/eche_tray.h"
 #include "ash/system/focus_mode/focus_mode_tray.h"
@@ -99,6 +100,8 @@ void StatusAreaWidget::Initialize() {
       AddTrayButton(std::make_unique<LogoutButtonTray>(shelf_));
   dictation_button_tray_ = AddTrayButton(std::make_unique<DictationButtonTray>(
       shelf_, TrayBackgroundViewCatalogName::kDictationStatusArea));
+  mouse_keys_tray_ = AddTrayButton(std::make_unique<MouseKeysTray>(
+      shelf_, TrayBackgroundViewCatalogName::kMouseKeysStatusArea));
   select_to_speak_tray_ = AddTrayButton(std::make_unique<SelectToSpeakTray>(
       shelf_, TrayBackgroundViewCatalogName::kSelectToSpeakStatusArea));
   ime_menu_tray_ = AddTrayButton(std::make_unique<ImeMenuTray>(shelf_));
@@ -298,6 +301,7 @@ void StatusAreaWidget::LogVisiblePodCountMetric() {
       case TrayBackgroundViewCatalogName::kWmMode:
       case TrayBackgroundViewCatalogName::kVideoConferenceTray:
       case TrayBackgroundViewCatalogName::kFocusMode:
+      case TrayBackgroundViewCatalogName::kMouseKeysStatusArea:
         if (!tray_button->GetVisible()) {
           continue;
         }

ash/system/status_area_widget.h

@@ -37,6 +37,7 @@ class PaletteTray;
 class PhoneHubTray;
 class PodsOverflowTray;
 class AnnotationTray;
+class MouseKeysTray;
 class SelectToSpeakTray;
 class Shelf;
 class StatusAreaAnimationController;
@@ -143,6 +144,7 @@ class ASH_EXPORT StatusAreaWidget : public SessionObserver,
   PhoneHubTray* phone_hub_tray() { return phone_hub_tray_; }
   EcheTray* eche_tray() { return eche_tray_; }
 
+  MouseKeysTray* mouse_keys_tray() { return mouse_keys_tray_; }
   SelectToSpeakTray* select_to_speak_tray() { return select_to_speak_tray_; }
   WmModeButtonTray* wm_mode_button_tray() { return wm_mode_button_tray_; }
 
@@ -301,6 +303,8 @@ class ASH_EXPORT StatusAreaWidget : public SessionObserver,
   raw_ptr<VirtualKeyboardTray, DanglingUntriaged> virtual_keyboard_tray_ =
       nullptr;
   raw_ptr<ImeMenuTray, DanglingUntriaged> ime_menu_tray_ = nullptr;
+  raw_ptr<MouseKeysTray, DisableDanglingPtrDetection> mouse_keys_tray_ =
+      nullptr;
   raw_ptr<SelectToSpeakTray, DanglingUntriaged> select_to_speak_tray_ = nullptr;
   raw_ptr<HoldingSpaceTray, DanglingUntriaged> holding_space_tray_ = nullptr;
   raw_ptr<WmModeButtonTray, DanglingUntriaged> wm_mode_button_tray_ = nullptr;