Leave ChromeOS system menu open when toggling nightlight.

ash/system/tray/system_menu_button.h

 // Copyright 2016 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_TRAY_SYSTEM_MENU_BUTTON_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_MENU_BUTTON_H_
 
 #include "ash/resources/vector_icons/vector_icons.h"
 #include "ash/system/tray/tray_popup_ink_drop_style.h"
 #include "base/macros.h"
@@ skipping 11 matching lines @@
 // crbug.com/614453.
 class SystemMenuButton : public views::ImageButton {
  public:
   // Constructs the button with |listener| and a centered icon corresponding to
   // |normal_icon| when button is enabled and |disabled_icon| when it is
   // disabled. |ink_drop_style| specifies which flavor of the ink drop should be
   // used. |accessible_name_id| corresponds to the string in ui::ResourceBundle
   // to use for the button's accessible and tooltip text.
   SystemMenuButton(views::ButtonListener* listener,
                    TrayPopupInkDropStyle ink_drop_style,
-                   gfx::ImageSkia normal_icon,
-                   gfx::ImageSkia disabled_icon,
+                   const gfx::ImageSkia& normal_icon,
+                   const gfx::ImageSkia& disabled_icon,
                    int accessible_name_id);
 
   // Similar to the above constructor. Just gets a single vector icon and
   // creates the normal and disabled icons based on that using default menu icon
   // colors.
   SystemMenuButton(views::ButtonListener* listener,
                    TrayPopupInkDropStyle ink_drop_style,
                    const gfx::VectorIcon& icon,
                    int accessible_name_id);
   ~SystemMenuButton() override;
 
+  // Sets the normal and disabled icons based on that using default menu icon
+  // colors.
+  void SetVectorIcon(const gfx::VectorIcon& icon);
+
   // Explicity sets the ink drop color. Otherwise the default value will be used
   // by TrayPopupUtils::CreateInkDropRipple() and
   // TrayPopupUtils::CreateInkDropHighlight().
   void SetInkDropColor(SkColor color);
 
   // views::ImageButton:
   std::unique_ptr<views::InkDrop> CreateInkDrop() override;
   std::unique_ptr<views::InkDropRipple> CreateInkDropRipple() const override;
   std::unique_ptr<views::InkDropHighlight> CreateInkDropHighlight()
       const override;
@@ skipping 10 matching lines @@
   // used as defined by TrayPopupUtils::CreateInkDropRipple() and
   // TrayPopupUtils::CreateInkDropHighlight().
   base::Optional<SkColor> ink_drop_color_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemMenuButton);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_MENU_BUTTON_H_