Leave ChromeOS system menu open when toggling nightlight.

ash/system/tray/system_menu_button.cc

Index: ash/system/tray/system_menu_button.cc
diff --git a/ash/system/tray/system_menu_button.cc b/ash/system/tray/system_menu_button.cc
index 8afd07b18853ff25e4353176e6e13574cc797df9..dc32f5049ecb2e9a529fb1c28dfcdad17a2c8990 100644
--- a/ash/system/tray/system_menu_button.cc
+++ b/ash/system/tray/system_menu_button.cc
@@ -22,15 +22,15 @@ namespace ash {
 
 SystemMenuButton::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)
     : views::ImageButton(listener), ink_drop_style_(ink_drop_style) {
   DCHECK_EQ(normal_icon.width(), disabled_icon.width());
   DCHECK_EQ(normal_icon.height(), disabled_icon.height());
 
-  SetImage(views::Button::STATE_NORMAL, &normal_icon);
-  SetImage(views::Button::STATE_DISABLED, &disabled_icon);
+  SetImage(views::Button::STATE_NORMAL, normal_icon);
+  SetImage(views::Button::STATE_DISABLED, disabled_icon);
 
   const int horizontal_padding = (kMenuButtonSize - normal_icon.width()) / 2;
   const int vertical_padding = (kMenuButtonSize - normal_icon.height()) / 2;
@@ -49,9 +49,18 @@ SystemMenuButton::SystemMenuButton(views::ButtonListener* listener,
                                    int accessible_name_id)
     : SystemMenuButton(listener,
                        ink_drop_style,
-                       gfx::CreateVectorIcon(icon, kMenuIconColor),
-                       gfx::CreateVectorIcon(icon, kMenuIconColorDisabled),
-                       accessible_name_id) {}
+                       gfx::ImageSkia(),
+                       gfx::ImageSkia(),
+                       accessible_name_id) {
+  SetVectorIcon(icon);
+}
+
+void SystemMenuButton::SetVectorIcon(const gfx::VectorIcon& icon) {
+  SetImage(views::Button::STATE_NORMAL,
+           gfx::CreateVectorIcon(icon, kMenuIconColor));
+  SetImage(views::Button::STATE_DISABLED,
+           gfx::CreateVectorIcon(icon, kMenuIconColorDisabled));
+}
 
 SystemMenuButton::~SystemMenuButton() {}