[Media Router] Add experiment control logic.

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

Index: chrome/browser/ui/webui/media_router/media_router_test.h
diff --git a/chrome/browser/ui/webui/media_router/media_router_test.h b/chrome/browser/ui/webui/media_router/media_router_test.h
index 6e89d5b6b0d6dc5da19d6153863ae2bdf2909f39..c311d6f47b24d9e37fc8587e0763e27b7385a206 100644
--- a/chrome/browser/ui/webui/media_router/media_router_test.h
+++ b/chrome/browser/ui/webui/media_router/media_router_test.h
@@ -6,6 +6,7 @@
 #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;
 
@@ -21,6 +22,7 @@ class MediaRouterTest : public BrowserWithTestWindowTest {
   BrowserWindow* CreateBrowserWindow() override;
 
  private:
+  extensions::FeatureSwitch::ScopedOverride feature_override_;
   DISALLOW_COPY_AND_ASSIGN(MediaRouterTest);
 };