Adds Select-to-Speak button in the tray.

The button will allow touch and stylus users to activate Select-to-Speak
without a keyboard, but is also able to be used with a mouse.

This adds a button to the tray that is notified and updates its appearence when
Select-to-Speak state changes. In a following change, the Select-to-Speak
extension will listen to state change requests from the button.

Bug: 753018
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I3a1ab08c579696cf199c32deec368473952b57fc
Reviewed-on: https://chromium-review.googlesource.com/1040268
Commit-Queue: Katie Dektar <katie@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555840}

ash/BUILD.gn

@@ -519,6 +519,8 @@ component("ash") {
     "sticky_keys/sticky_keys_overlay.cc",
     "sticky_keys/sticky_keys_overlay.h",
     "sticky_keys/sticky_keys_state.h",
+    "system/accessibility/select_to_speak_tray.cc",
+    "system/accessibility/select_to_speak_tray.h",
     "system/audio/audio_detailed_view.cc",
     "system/audio/audio_detailed_view.h",
     "system/audio/tray_audio.cc",
@@ -1631,6 +1633,7 @@ test("ash_unittests") {
     "shell_unittest.cc",
     "sticky_keys/sticky_keys_overlay_unittest.cc",
     "sticky_keys/sticky_keys_unittest.cc",
+    "system/accessibility/select_to_speak_tray_unittest.cc",
     "system/audio/tray_audio_unittest.cc",
     "system/bluetooth/bluetooth_power_controller_unittest.cc",
     "system/bluetooth/tray_bluetooth_helper_unittest.cc",

ash/accessibility/test_accessibility_controller_client.cc

@@ -61,7 +61,9 @@ void TestAccessibilityControllerClient::ShouldToggleSpokenFeedbackViaTouch(
 void TestAccessibilityControllerClient::PlaySpokenFeedbackToggleCountdown(
     int tick_count) {}
 
-void TestAccessibilityControllerClient::RequestSelectToSpeakStateChange() {}
+void TestAccessibilityControllerClient::RequestSelectToSpeakStateChange() {
+  ++select_to_speak_state_change_requests_;
+}
 
 int32_t TestAccessibilityControllerClient::GetPlayedEarconAndReset() {
   int32_t tmp = sound_key_;

ash/accessibility/test_accessibility_controller_client.h

@@ -45,6 +45,9 @@ class TestAccessibilityControllerClient
 
   mojom::AccessibilityAlert last_a11y_alert() const { return last_a11y_alert_; }
   ax::mojom::Gesture last_a11y_gesture() const { return last_a11y_gesture_; }
+  int select_to_speak_change_change_requests() const {
+    return select_to_speak_state_change_requests_;
+  }
 
  private:
   mojom::AccessibilityAlert last_a11y_alert_ = mojom::AccessibilityAlert::NONE;
@@ -54,6 +57,8 @@ class TestAccessibilityControllerClient
 
   ax::mojom::Gesture last_a11y_gesture_ = ax::mojom::Gesture::kNone;
 
+  int select_to_speak_state_change_requests_ = 0;
+
   mojo::Binding<mojom::AccessibilityControllerClient> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(TestAccessibilityControllerClient);

ash/ash_strings.grd

@@ -1082,6 +1082,10 @@ This file contains the strings for ash.
         IME menu 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>
+
       <!-- Deprecated Accelerators Messages -->
       <!-- Shortcut keys MUST be connected with pluses (e.g. Ctrl+Shift+L). -->
       <message name="IDS_SHORTCUT_LOCK_SCREEN_OLD" desc="the old deprecated shortcut to lock the screen.">

ash/resources/vector_icons/BUILD.gn

@@ -165,7 +165,9 @@ aggregate_vector_icons("ash_vector_icons") {
     "system_tray_recording.icon",
     "system_tray_rotation_lock_auto.icon",
     "system_tray_rotation_lock_locked.icon",
+    "system_tray_select_to_speak.icon",
     "system_tray_screen_share.icon",
+    "system_tray_stop.icon",
     "system_tray_tracing.icon",
     "system_tray_update.icon",
     "system_tray_volume_mute.icon",

ash/resources/vector_icons/system_tray_select_to_speak.icon

+// 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.
+
+CANVAS_DIMENSIONS, 32,
+MOVE_TO, 16, 28,
+CUBIC_TO, 9.37f, 28, 4, 22.63f, 4, 16,
+CUBIC_TO, 4, 9.37f, 9.37f, 4, 16, 4,
+CUBIC_TO, 22.63f, 4, 28, 9.37f, 28, 16,
+CUBIC_TO, 28, 22.63f, 22.63f, 28, 16, 28,
+CLOSE,
+MOVE_TO, 8, 8,
+LINE_TO, 8, 12,
+LINE_TO, 10, 12,
+LINE_TO, 10, 10,
+LINE_TO, 12, 10,
+LINE_TO, 12, 8,
+LINE_TO, 8, 8,
+CLOSE,
+MOVE_TO, 24, 24,
+LINE_TO, 24, 20,
+LINE_TO, 22, 20,
+LINE_TO, 22, 22,
+LINE_TO, 20, 22,
+LINE_TO, 20, 24,
+LINE_TO, 24, 24,
+CLOSE,
+MOVE_TO, 10, 13.95f,
+LINE_TO, 10, 18.05f,
+LINE_TO, 12.67f, 18.05f,
+LINE_TO, 16, 21.47f,
+LINE_TO, 16, 10.53f,
+LINE_TO, 12.67f, 13.95f,
+LINE_TO, 10, 13.95f,
+CLOSE,
+MOVE_TO, 19, 16,
+CUBIC_TO, 19, 14.79f, 18.32f, 13.75f, 17.33f, 13.24f,
+LINE_TO, 17.33f, 18.75f,
+CUBIC_TO, 18.32f, 18.25f, 19, 17.21f, 19, 16,
+CLOSE,
+MOVE_TO, 17.33f, 10,
+LINE_TO, 17.33f, 11.41f,
+CUBIC_TO, 19.26f, 12, 20.67f, 13.83f, 20.67f, 16,
+CUBIC_TO, 20.67f, 18.17f, 19.26f, 20, 17.33f, 20.59f,
+LINE_TO, 17.33f, 22,
+CUBIC_TO, 20.01f, 21.38f, 22, 18.93f, 22, 16,
+CUBIC_TO, 22, 13.07f, 20.01f, 10.62f, 17.33f, 10,
+CLOSE
+
+CANVAS_DIMENSIONS, 16,
+MOVE_TO, 8, 14,
+CUBIC_TO, 4.69f, 14, 2, 11.31f, 2, 8,
+CUBIC_TO, 2, 4.69f, 4.69f, 2, 8, 2,
+CUBIC_TO, 11.31f, 2, 14, 4.69f, 14, 8,
+CUBIC_TO, 14, 11.31f, 11.31f, 14, 8, 14,
+CLOSE,
+MOVE_TO, 4, 4,
+LINE_TO, 4, 6,
+LINE_TO, 5, 6,
+LINE_TO, 5, 5,
+LINE_TO, 6, 5,
+LINE_TO, 6, 4,
+LINE_TO, 4, 4,
+CLOSE,
+MOVE_TO, 12, 12,
+LINE_TO, 12, 10,
+LINE_TO, 11, 10,
+LINE_TO, 11, 11,
+LINE_TO, 10, 11,
+LINE_TO, 10, 12,
+LINE_TO, 12, 12,
+CLOSE,
+MOVE_TO, 5, 6.97f,
+LINE_TO, 5, 9.03f,
+LINE_TO, 6.33f, 9.03f,
+LINE_TO, 8, 10.74f,
+LINE_TO, 8, 5.26f,
+LINE_TO, 6.33f, 6.97f,
+LINE_TO, 5, 6.97f,
+CLOSE,
+MOVE_TO, 9.5f, 8,
+CUBIC_TO, 9.5f, 7.39f, 9.16f, 6.87f, 8.67f, 6.62f,
+LINE_TO, 8.67f, 9.38f,
+CUBIC_TO, 9.16f, 9.13f, 9.5f, 8.61f, 9.5f, 8,
+CLOSE,
+MOVE_TO, 8.67f, 5,
+LINE_TO, 8.67f, 5.7f,
+CUBIC_TO, 9.63f, 6, 10.33f, 6.92f, 10.33f, 8,
+CUBIC_TO, 10.33f, 9.08f, 9.63f, 10, 8.67f, 10.3f,
+LINE_TO, 8.67f, 11,
+CUBIC_TO, 10, 10.69f, 11, 9.46f, 11, 8,
+CUBIC_TO, 11, 6.54f, 10, 5.31f, 8.67f, 5,
+CLOSE
\ No newline at end of file

ash/resources/vector_icons/system_tray_stop.icon

+// 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.
+
+CANVAS_DIMENSIONS, 32,
+MOVE_TO, 16, 28,
+CUBIC_TO, 9.37f, 28, 4, 22.63f, 4, 16,
+CUBIC_TO, 4, 9.37f, 9.37f, 4, 16, 4,
+CUBIC_TO, 22.63f, 4, 28, 9.37f, 28, 16,
+CUBIC_TO, 28, 22.63f, 22.63f, 28, 16, 28,
+CLOSE,
+MOVE_TO, 12, 12,
+LINE_TO, 12, 20,
+LINE_TO, 20, 20,
+LINE_TO, 20, 12,
+LINE_TO, 12, 12,
+CLOSE
+
+CANVAS_DIMENSIONS, 16,
+MOVE_TO, 8, 14,
+CUBIC_TO, 4.69f, 14, 2, 11.31f, 2, 8,
+CUBIC_TO, 2, 4.69f, 4.69f, 2, 8, 2,
+CUBIC_TO, 11.31f, 2, 14, 4.69f, 14, 8,
+CUBIC_TO, 14, 11.31f, 11.31f, 14, 8, 14,
+CLOSE,
+MOVE_TO, 6, 6,
+LINE_TO, 6, 10,
+LINE_TO, 10, 10,
+LINE_TO, 10, 6,
+LINE_TO, 6, 6,
+CLOSE
\ No newline at end of file

ash/system/accessibility/select_to_speak_tray.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/system/accessibility/select_to_speak_tray.h"
+
+#include "ash/accessibility/accessibility_controller.h"
+#include "ash/resources/vector_icons/vector_icons.h"
+#include "ash/shelf/shelf_constants.h"
+#include "ash/shell.h"
+#include "ash/strings/grit/ash_strings.h"
+#include "ash/system/tray/tray_constants.h"
+#include "ash/system/tray/tray_container.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/paint_vector_icon.h"
+#include "ui/views/border.h"
+#include "ui/views/controls/image_view.h"
+
+namespace views {
+class ImageView;
+}
+
+namespace ash {
+
+// This constant must be kept the same as SELECT_TO_SPEAK_TRAY_CLASS_NAME in
+// chrome/browser/resources/chromeos/select_to_speak/select_to_speak.js.
+const char kSelectToSpeakTrayClassName[] =
+    "tray/TrayBackgroundView/SelectToSpeakTray";
+
+SelectToSpeakTray::SelectToSpeakTray(Shelf* shelf)
+    : TrayBackgroundView(shelf), icon_(new views::ImageView()) {
+  SetInkDropMode(InkDropMode::ON);
+
+  start_selection_image_ =
+      gfx::CreateVectorIcon(kSystemTraySelectToSpeakIcon, kShelfIconColor);
+  cancel_speech_image_ =
+      gfx::CreateVectorIcon(kSystemTrayStopIcon, kShelfIconColor);
+  icon_->SetImage(start_selection_image_);
+  const int vertical_padding =
+      (kTrayItemSize - start_selection_image_.height()) / 2;
+  const int horizontal_padding =
+      (kTrayItemSize - start_selection_image_.width()) / 2;
+  icon_->SetBorder(views::CreateEmptyBorder(
+      gfx::Insets(vertical_padding, horizontal_padding)));
+  tray_container()->AddChildView(icon_);
+  CheckStatusAndUpdateIcon();
+
+  // Observe the accessibility controller state changes to know when Select to
+  // Speak state is updated or when it is disabled/enabled.
+  Shell::Get()->accessibility_controller()->AddObserver(this);
+}
+
+SelectToSpeakTray::~SelectToSpeakTray() {
+  Shell::Get()->accessibility_controller()->RemoveObserver(this);
+}
+
+base::string16 SelectToSpeakTray::GetAccessibleNameForTray() {
+  return l10n_util::GetStringUTF16(
+      IDS_ASH_SELECT_TO_SPEAK_TRAY_ACCESSIBLE_NAME);
+}
+
+const char* SelectToSpeakTray::GetClassName() const {
+  return kSelectToSpeakTrayClassName;
+}
+
+bool SelectToSpeakTray::PerformAction(const ui::Event& event) {
+  Shell::Get()->accessibility_controller()->RequestSelectToSpeakStateChange();
+  return true;
+}
+
+void SelectToSpeakTray::OnAccessibilityStatusChanged() {
+  CheckStatusAndUpdateIcon();
+}
+
+void SelectToSpeakTray::CheckStatusAndUpdateIcon() {
+  if (!Shell::Get()->accessibility_controller()->IsSelectToSpeakEnabled()) {
+    SetVisible(false);
+    return;
+  }
+
+  ash::mojom::SelectToSpeakState state =
+      Shell::Get()->accessibility_controller()->GetSelectToSpeakState();
+  switch (state) {
+    case ash::mojom::SelectToSpeakState::kSelectToSpeakStateInactive:
+      icon_->SetImage(start_selection_image_);
+      SetIsActive(false);
+      break;
+    case ash::mojom::SelectToSpeakState::kSelectToSpeakStateSelecting:
+      // Activate the start selection button during selection.
+      icon_->SetImage(start_selection_image_);
+      SetIsActive(true);
+      break;
+    case ash::mojom::SelectToSpeakState::kSelectToSpeakStateSpeaking:
+      icon_->SetImage(cancel_speech_image_);
+      SetIsActive(true);
+      break;
+  }
+
+  SetVisible(true);
+}
+
+}  // namespace ash

ash/system/accessibility/select_to_speak_tray.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_SYSTEM_ACCESSIBILITY_SELECT_TO_SPEAK_TRAY_H_
+#define ASH_SYSTEM_ACCESSIBILITY_SELECT_TO_SPEAK_TRAY_H_
+
+#include "ash/accessibility/accessibility_observer.h"
+#include "ash/ash_export.h"
+#include "ash/system/tray/tray_background_view.h"
+#include "base/macros.h"
+#include "ui/views/controls/image_view.h"
+
+namespace views {
+class ImageView;
+}
+
+namespace ash {
+
+// A button in the tray that lets users start/stop Select-to-Speak.
+class ASH_EXPORT SelectToSpeakTray : public TrayBackgroundView,
+                                     public AccessibilityObserver {
+ public:
+  explicit SelectToSpeakTray(Shelf* shelf);
+  ~SelectToSpeakTray() override;
+
+  // TrayBackgroundView:
+  base::string16 GetAccessibleNameForTray() override;
+  const char* GetClassName() const override;
+  void HideBubbleWithView(const views::TrayBubbleView* bubble_view) override {}
+  void ClickedOutsideBubble() override {}
+  bool PerformAction(const ui::Event& event) override;
+
+  // AccessibilityObserver:
+  void OnAccessibilityStatusChanged() override;
+
+ private:
+  friend class SelectToSpeakTrayTest;
+
+  // Sets the icon when select-to-speak is activated (speaking) / deactivated.
+  // Also updates visibility when select-to-speak is enabled / disabled.
+  void CheckStatusAndUpdateIcon();
+
+  gfx::ImageSkia start_selection_image_;
+  gfx::ImageSkia cancel_speech_image_;
+
+  // Weak pointer, will be parented by TrayContainer for its lifetime.
+  views::ImageView* icon_;
+
+  DISALLOW_COPY_AND_ASSIGN(SelectToSpeakTray);
+};
+
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_ACCESSIBILITY_SELECT_TO_SPEAK_TRAY_H_

ash/system/accessibility/select_to_speak_tray_unittest.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/system/accessibility/select_to_speak_tray.h"
+
+#include "ash/accelerators/accelerator_controller.h"
+#include "ash/accessibility/accessibility_controller.h"
+#include "ash/accessibility/test_accessibility_controller_client.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/command_line.h"
+#include "base/run_loop.h"
+#include "base/strings/utf_string_conversions.h"
+#include "ui/accessibility/ax_node_data.h"
+#include "ui/base/ime/ime_bridge.h"
+#include "ui/base/ime/text_input_flags.h"
+#include "ui/events/event.h"
+#include "ui/views/controls/label.h"
+
+namespace ash {
+
+namespace {
+
+SelectToSpeakTray* GetTray() {
+  return StatusAreaWidgetTestHelper::GetStatusAreaWidget()
+      ->select_to_speak_tray();
+}
+
+ui::GestureEvent CreateTapEvent() {
+  return ui::GestureEvent(0, 0, 0, base::TimeTicks(),
+                          ui::GestureEventDetails(ui::ET_GESTURE_TAP));
+}
+
+}  // namespace
+
+class SelectToSpeakTrayTest : public AshTestBase {
+ public:
+  SelectToSpeakTrayTest() = default;
+  ~SelectToSpeakTrayTest() override = default;
+
+  void SetUp() override {
+    base::CommandLine::ForCurrentProcess()->AppendSwitch(
+        chromeos::switches::kEnableExperimentalAccessibilityFeatures);
+    AshTestBase::SetUp();
+    Shell::Get()->accessibility_controller()->SetSelectToSpeakEnabled(true);
+  }
+
+ protected:
+  // Returns true if the Select to Speak tray is visible.
+  bool IsVisible() { return GetTray()->visible(); }
+
+  // Returns true if the background color of the tray is active.
+  bool IsTrayBackgroundActive() { return GetTray()->is_active(); }
+
+  // Gets the current tray image view.
+  views::ImageView* GetImageView() { return GetTray()->icon_; }
+
+  gfx::ImageSkia GetStartSelectionImage() {
+    return GetTray()->start_selection_image_;
+  }
+
+  gfx::ImageSkia GetCancelSpeechImage() {
+    return GetTray()->cancel_speech_image_;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SelectToSpeakTrayTest);
+};
+
+// Ensures that creation doesn't cause any crashes and adds the image icon.
+// Also checks that the tray is visible.
+TEST_F(SelectToSpeakTrayTest, BasicConstruction) {
+  EXPECT_TRUE(GetImageView());
+  EXPECT_TRUE(IsVisible());
+}
+
+// Tests the icon disapears when select-to-speak is disabled and re-appears
+// when it is enabled.
+TEST_F(SelectToSpeakTrayTest, ShowsAndHidesWithSelectToSpeakEnabled) {
+  Shell::Get()->accessibility_controller()->SetSelectToSpeakEnabled(false);
+  EXPECT_FALSE(IsVisible());
+  Shell::Get()->accessibility_controller()->SetSelectToSpeakEnabled(true);
+  EXPECT_TRUE(IsVisible());
+}
+
+// Test that clicking the button sends a Select to Speak state change request.
+TEST_F(SelectToSpeakTrayTest, ButtonRequestsSelectToSpeakStateChange) {
+  AccessibilityController* controller =
+      Shell::Get()->accessibility_controller();
+  TestAccessibilityControllerClient client;
+  controller->SetClient(client.CreateInterfacePtrAndBind());
+
+  EXPECT_EQ(0, client.select_to_speak_change_change_requests());
+
+  GetTray()->PerformAction(CreateTapEvent());
+  controller->FlushMojoForTest();
+  EXPECT_EQ(1, client.select_to_speak_change_change_requests());
+
+  GetTray()->PerformAction(CreateTapEvent());
+  controller->FlushMojoForTest();
+  EXPECT_EQ(2, client.select_to_speak_change_change_requests());
+}
+
+// Test that changing the SelectToSpeakState in the AccessibilityController
+// results in a change of icon and activation in the tray.
+TEST_F(SelectToSpeakTrayTest, SelectToSpeakStateImpactsImageAndActivation) {
+  AccessibilityController* controller =
+      Shell::Get()->accessibility_controller();
+  controller->SetSelectToSpeakState(
+      ash::mojom::SelectToSpeakState::kSelectToSpeakStateSelecting);
+  EXPECT_TRUE(IsTrayBackgroundActive());
+  EXPECT_TRUE(GetStartSelectionImage().BackedBySameObjectAs(
+      GetImageView()->GetImage()));
+
+  controller->SetSelectToSpeakState(
+      ash::mojom::SelectToSpeakState::kSelectToSpeakStateSpeaking);
+  EXPECT_TRUE(IsTrayBackgroundActive());
+  EXPECT_TRUE(
+      GetCancelSpeechImage().BackedBySameObjectAs(GetImageView()->GetImage()));
+
+  controller->SetSelectToSpeakState(
+      ash::mojom::SelectToSpeakState::kSelectToSpeakStateInactive);
+  EXPECT_FALSE(IsTrayBackgroundActive());
+  EXPECT_TRUE(GetStartSelectionImage().BackedBySameObjectAs(
+      GetImageView()->GetImage()));
+}
+
+}  // namespace ash

ash/system/status_area_widget.cc

@@ -9,6 +9,7 @@
 #include "ash/session/session_controller.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shell.h"
+#include "ash/system/accessibility/select_to_speak_tray.h"
 #include "ash/system/dictation/dictation_button_tray.h"
 #include "ash/system/flag_warning/flag_warning_tray.h"
 #include "ash/system/ime_menu/ime_menu_tray.h"
@@ -73,16 +74,22 @@ void StatusAreaWidget::Initialize() {
   ime_menu_tray_ = std::make_unique<ImeMenuTray>(shelf_);
   status_area_widget_delegate_->AddChildView(ime_menu_tray_.get());
 
-  logout_button_tray_ = std::make_unique<LogoutButtonTray>(shelf_);
-  status_area_widget_delegate_->AddChildView(logout_button_tray_.get());
-
-  // Dictation is currently only available behind the experimental
-  // accessibility features flag.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           chromeos::switches::kEnableExperimentalAccessibilityFeatures)) {
+    // The Select-to-Speak button is currently only available behind the
+    // experimental accessibility features flag.
+    select_to_speak_tray_ = std::make_unique<SelectToSpeakTray>(shelf_);
+    status_area_widget_delegate_->AddChildView(select_to_speak_tray_.get());
+
+    // Dictation is currently only available behind the experimental
+    // accessibility features flag.
     dictation_button_tray_ = std::make_unique<DictationButtonTray>(shelf_);
     status_area_widget_delegate_->AddChildView(dictation_button_tray_.get());
   }
+
+  logout_button_tray_ = std::make_unique<LogoutButtonTray>(shelf_);
+  status_area_widget_delegate_->AddChildView(logout_button_tray_.get());
+
   if (Shell::GetAshConfig() == ash::Config::MASH) {
     // Flag warning tray is not currently used in non-MASH environments, because
     // mus will roll out via experiment/Finch trial and showing the tray would
@@ -105,9 +112,11 @@ void StatusAreaWidget::Initialize() {
   palette_tray_->Initialize();
   virtual_keyboard_tray_->Initialize();
   ime_menu_tray_->Initialize();
-  overview_button_tray_->Initialize();
+  if (select_to_speak_tray_)
+    select_to_speak_tray_->Initialize();
   if (dictation_button_tray_)
     dictation_button_tray_->Initialize();
+  overview_button_tray_->Initialize();
   UpdateAfterShelfAlignmentChange();
   UpdateAfterLoginStatusChange(
       Shell::Get()->session_controller()->login_status());
@@ -124,11 +133,12 @@ StatusAreaWidget::~StatusAreaWidget() {
   system_tray_.reset();
   unified_system_tray_.reset();
   ime_menu_tray_.reset();
+  select_to_speak_tray_.reset();
+  dictation_button_tray_.reset();
   virtual_keyboard_tray_.reset();
   palette_tray_.reset();
   logout_button_tray_.reset();
   overview_button_tray_.reset();
-  dictation_button_tray_.reset();
   flag_warning_tray_.reset();
 
   // All child tray views have been removed.
@@ -142,10 +152,12 @@ void StatusAreaWidget::UpdateAfterShelfAlignmentChange() {
   logout_button_tray_->UpdateAfterShelfAlignmentChange();
   virtual_keyboard_tray_->UpdateAfterShelfAlignmentChange();
   ime_menu_tray_->UpdateAfterShelfAlignmentChange();
-  palette_tray_->UpdateAfterShelfAlignmentChange();
-  overview_button_tray_->UpdateAfterShelfAlignmentChange();
+  if (select_to_speak_tray_)
+    select_to_speak_tray_->UpdateAfterShelfAlignmentChange();
   if (dictation_button_tray_)
     dictation_button_tray_->UpdateAfterShelfAlignmentChange();
+  palette_tray_->UpdateAfterShelfAlignmentChange();
+  overview_button_tray_->UpdateAfterShelfAlignmentChange();
   if (flag_warning_tray_)
     flag_warning_tray_->UpdateAfterShelfAlignmentChange();
   status_area_widget_delegate_->UpdateLayout();
@@ -204,10 +216,12 @@ void StatusAreaWidget::SchedulePaint() {
   virtual_keyboard_tray_->SchedulePaint();
   logout_button_tray_->SchedulePaint();
   ime_menu_tray_->SchedulePaint();
-  palette_tray_->SchedulePaint();
-  overview_button_tray_->SchedulePaint();
+  if (select_to_speak_tray_)
+    select_to_speak_tray_->SchedulePaint();
   if (dictation_button_tray_)
     dictation_button_tray_->SchedulePaint();
+  palette_tray_->SchedulePaint();
+  overview_button_tray_->SchedulePaint();
   if (flag_warning_tray_)
     flag_warning_tray_->SchedulePaint();
 }
@@ -230,10 +244,12 @@ void StatusAreaWidget::UpdateShelfItemBackground(SkColor color) {
   system_tray_->UpdateShelfItemBackground(color);
   virtual_keyboard_tray_->UpdateShelfItemBackground(color);
   ime_menu_tray_->UpdateShelfItemBackground(color);
-  palette_tray_->UpdateShelfItemBackground(color);
-  overview_button_tray_->UpdateShelfItemBackground(color);
+  if (select_to_speak_tray_)
+    select_to_speak_tray_->UpdateShelfItemBackground(color);
   if (dictation_button_tray_)
     dictation_button_tray_->UpdateShelfItemBackground(color);
+  palette_tray_->UpdateShelfItemBackground(color);
+  overview_button_tray_->UpdateShelfItemBackground(color);
 }
 
 }  // namespace ash

ash/system/status_area_widget.h

@@ -23,6 +23,7 @@ class LogoutButtonTray;
 class OverviewButtonTray;
 class DictationButtonTray;
 class PaletteTray;
+class SelectToSpeakTray;
 class Shelf;
 class StatusAreaWidgetDelegate;
 class SystemTray;
@@ -81,6 +82,9 @@ class ASH_EXPORT StatusAreaWidget : public views::Widget,
   }
   PaletteTray* palette_tray() { return palette_tray_.get(); }
   ImeMenuTray* ime_menu_tray() { return ime_menu_tray_.get(); }
+  SelectToSpeakTray* select_to_speak_tray() {
+    return select_to_speak_tray_.get();
+  }
 
   Shelf* shelf() { return shelf_; }
 
@@ -128,6 +132,7 @@ class ASH_EXPORT StatusAreaWidget : public views::Widget,
   std::unique_ptr<PaletteTray> palette_tray_;
   std::unique_ptr<VirtualKeyboardTray> virtual_keyboard_tray_;
   std::unique_ptr<ImeMenuTray> ime_menu_tray_;
+  std::unique_ptr<SelectToSpeakTray> select_to_speak_tray_;
   std::unique_ptr<FlagWarningTray> flag_warning_tray_;
 
   LoginStatus login_status_ = LoginStatus::NOT_LOGGED_IN;