[Media Router] Add experiment control logic.

chrome/browser/ui/webui/media_router/media_router_test.h

 // Copyright 2015 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 CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_MEDIA_ROUTER_TEST_H_
 #define CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_MEDIA_ROUTER_TEST_H_
 
 #include "chrome/test/base/browser_with_test_window_test.h"
+#include "extensions/common/feature_switch.h"
 
 class BrowserWindow;
 
 class MediaRouterTest : public BrowserWithTestWindowTest {
  public:
   MediaRouterTest();
   ~MediaRouterTest() override;
 
  protected:
-  void SetUp() override;
-
   // BrowserWithTestWindowTest override.
   BrowserWindow* CreateBrowserWindow() override;
 
  private:
+  extensions::FeatureSwitch::ScopedOverride feature_override_;
   DISALLOW_COPY_AND_ASSIGN(MediaRouterTest);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_MEDIA_ROUTER_TEST_H_