Hide Night Light behind a flag

ash/system/tiles/tray_tiles_unittest.cc

 // 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.
 
 #include "ash/system/tiles/tray_tiles.h"
 
+#include "ash/ash_switches.h"
+#include "ash/system/night_light/night_light_controller.h"
 #include "ash/system/night_light/night_light_toggle_button.h"
 #include "ash/system/tiles/tiles_default_view.h"
 #include "ash/system/tray/system_menu_button.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/test/test_session_controller_client.h"
+#include "base/command_line.h"
 #include "components/user_manager/user_type.h"
 #include "ui/views/view.h"
 
 using views::Button;
 
 namespace ash {
 
 // Tests manually control their session state.
 class TrayTilesTest : public test::NoSessionAshTestBase {
  public:
   TrayTilesTest() {}
   ~TrayTilesTest() override {}
 
   void SetUp() override {
+    // Explicitly enable the NightLight feature for the tests.
+    base::CommandLine::ForCurrentProcess()->AppendSwitch(
+        ash::switches::kAshEnableNightLight);
+
     test::NoSessionAshTestBase::SetUp();
     tray_tiles_.reset(new TrayTiles(GetPrimarySystemTray()));
   }
 
   void TearDown() override {
     tray_tiles_.reset();
     test::NoSessionAshTestBase::TearDown();
   }
 
   views::CustomButton* GetSettingsButton() {
@@ skipping 81 matching lines @@
   std::unique_ptr<views::View> default_view(
       tray_tiles()->CreateDefaultViewForTesting());
   EXPECT_EQ(Button::STATE_DISABLED, GetSettingsButton()->state());
   EXPECT_EQ(Button::STATE_DISABLED, GetHelpButton()->state());
   EXPECT_EQ(Button::STATE_DISABLED, GetNightLightButton()->state());
   EXPECT_EQ(Button::STATE_DISABLED, GetLockButton()->state());
   EXPECT_EQ(Button::STATE_NORMAL, GetPowerButton()->state());
 }
 
 }  // namespace ash