[Night Light] Accessibility: Make ChromeVox speak button status on toggles

ash/system/night_light/night_light_toggle_button.cc

Index: ash/system/night_light/night_light_toggle_button.cc
diff --git a/ash/system/night_light/night_light_toggle_button.cc b/ash/system/night_light/night_light_toggle_button.cc
index 231d6557b9563bd5536ecc923f0f6d550ad75458..74b0d451e4b2738ee2641405a0b8851cfb8aa423 100644
--- a/ash/system/night_light/night_light_toggle_button.cc
+++ b/ash/system/night_light/night_light_toggle_button.cc
@@ -9,6 +9,7 @@
 #include "ash/system/night_light/night_light_controller.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_popup_item_style.h"
+#include "ui/accessibility/ax_enums.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/paint_vector_icon.h"
@@ -54,6 +55,13 @@ NightLightToggleButton::NightLightToggleButton(views::ButtonListener* listener)
   Update();
 }
 
+void NightLightToggleButton::Toggle() {
+  DCHECK(NightLightController::IsFeatureEnabled());
+  Shell::Get()->night_light_controller()->Toggle();
+  Update();
+  NotifyAccessibilityEvent(ui::AX_EVENT_ARIA_ATTRIBUTE_CHANGED, true);
+}
+
 void NightLightToggleButton::Update() {
   const bool night_light_enabled =
       Shell::Get()->night_light_controller()->GetEnabled();