[Night Light] CL2: Ash and system tray work

ash/system/night_light/tray_night_light_unittest.cc

+// Copyright 2017 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/night_light/tray_night_light.h"
+
+#include "ash/shell.h"
+#include "ash/system/night_light/night_light_controller.h"
+#include "ash/system/tray/system_tray.h"
+#include "ash/test/ash_test_base.h"
+
+namespace ash {
+
+namespace {
+
+using TrayNightLightTest = test::AshTestBase;
+
+// Tests that when NightLight is active, its tray icon in the System Tray is
+// visible.
+TEST_F(TrayNightLightTest, TestNightLightTrayVisibility) {
+  SystemTray* tray = GetPrimarySystemTray();
+  TrayNightLight* tray_night_light = tray->tray_night_light();
+  NightLightController* controller = Shell::Get()->night_light_controller();
+  controller->SetEnabled(false);
+  ASSERT_FALSE(controller->enabled());
+  EXPECT_FALSE(tray_night_light->tray_view()->visible());
+  controller->SetEnabled(true);
+  EXPECT_TRUE(tray_night_light->tray_view()->visible());
+}
+
+}  // namespace
+
+}  // namespace ash