[Chrome OS MD] Implement accessibility detailed view for the MD Ash system menu

ash/common/system/tray_accessibility.h

 // Copyright (c) 2012 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_COMMON_SYSTEM_TRAY_ACCESSIBILITY_H_
 #define ASH_COMMON_SYSTEM_TRAY_ACCESSIBILITY_H_
 
 #include <stdint.h>
 
 #include "ash/common/accessibility_delegate.h"
 #include "ash/common/shell_observer.h"
 #include "ash/common/system/accessibility_observer.h"
 #include "ash/common/system/tray/tray_details_view.h"
 #include "ash/common/system/tray/tray_image_item.h"
 #include "ash/common/system/tray/tray_notification_view.h"
 #include "base/macros.h"
 #include "ui/gfx/font.h"
 #include "ui/views/controls/button/button.h"
 
 namespace chromeos {
 class TrayAccessibilityTest;
 }
 
+namespace gfx {
+struct VectorIcon;
+}
+
 namespace views {
 class Button;
 class ImageView;
 class Label;
 class View;
 }
 
 namespace ash {
 class HoverHighlightView;
 class SystemTrayItem;
 
 namespace tray {
 
 class AccessibilityPopupView : public TrayNotificationView {
  public:
   AccessibilityPopupView(SystemTrayItem* owner, uint32_t enabled_state_bits);
 
   const views::Label* label_for_test() const { return label_; }
 
  private:
   views::Label* CreateLabel(uint32_t enabled_state_bits);
 
   views::Label* label_;
 
   DISALLOW_COPY_AND_ASSIGN(AccessibilityPopupView);
 };
 
+// Create the detailed view of accessibility tray.
 class AccessibilityDetailedView : public TrayDetailsView,
                                   public ShellObserver {
  public:
   AccessibilityDetailedView(SystemTrayItem* owner, LoginStatus login);
   ~AccessibilityDetailedView() override {}
 
  private:
   // TrayDetailsView:
   void HandleViewClicked(views::View* view) override;
   void HandleButtonPressed(views::Button* sender,
                            const ui::Event& event) override;
 
   // Add the accessibility feature list.
   void AppendAccessibilityList();
 
-  // Add help entries.
+  // Add help entries. Only used for non-MD.
   void AppendHelpEntries();
 
+  // Helper function to create entries in the detailed accessibility view. The
+  // |icon| parameter is used to create button icons for MD only.
   HoverHighlightView* AddScrollListItem(const base::string16& text,
                                         bool highlight,
-                                        bool checked);
+                                        bool checked,
+                                        const gfx::VectorIcon& icon);
 
   views::View* spoken_feedback_view_;
   views::View* high_contrast_view_;
   views::View* screen_magnifier_view_;
   views::View* large_cursor_view_;
   views::View* help_view_;
   views::View* settings_view_;
   views::View* autoclick_view_;
   views::View* virtual_keyboard_view_;
 
@@ skipping 49 matching lines @@
   // A11y feature status on just entering the lock screen.
   bool show_a11y_menu_on_lock_screen_;
 
   friend class chromeos::TrayAccessibilityTest;
   DISALLOW_COPY_AND_ASSIGN(TrayAccessibility);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_ACCESSIBILITY_H_