MD Settings: enable by default in client

chrome/browser/ui/webui/options/options_ui_browsertest.h

 // Copyright (c) 2012 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_OPTIONS_OPTIONS_UI_BROWSERTEST_H_
 #define CHROME_BROWSER_UI_WEBUI_OPTIONS_OPTIONS_UI_BROWSERTEST_H_
 
 #include <string>
 
 #include "base/macros.h"
+#include "base/test/scoped_feature_list.h"
 #include "chrome/test/base/in_process_browser_test.h"
 
 namespace content {
 class RenderFrameHost;
 }
 
 namespace options {
 
 class OptionsUIBrowserTest : public InProcessBrowserTest {
  public:
   OptionsUIBrowserTest();
 
+  void SetUpInProcessBrowserTestFixture() override;
+
   // Navigate to the Uber/Settings page and block until it has loaded.
   void NavigateToSettings();
 
   // Navigate to a certain subpage in the Uber/Settings page and block until it
   // has loaded.
   void NavigateToSettingsSubpage(const std::string& sub_page);
 
   // Navigate to the Settings frame and block until complete.
   void NavigateToSettingsFrame();
 
   // Check navbar's existence.
   void VerifyNavbar();
 
   // Verify that the page title is correct.
   // The only guarantee we can make about the title of a settings tab is that
   // it should contain IDS_SETTINGS_TITLE somewhere.
   void VerifyTitle();
 
  protected:
   // Returns the RenderFrameHost associated with the Settings frame inside the
   // Uber UI page (which must be already loaded).
   content::RenderFrameHost* GetSettingsFrame();
 
  private:
+  base::test::ScopedFeatureList disable_md_settings_;
+
   DISALLOW_COPY_AND_ASSIGN(OptionsUIBrowserTest);
 };
 
 }  // namespace options
 
 #endif  // CHROME_BROWSER_UI_WEBUI_OPTIONS_OPTIONS_UI_BROWSERTEST_H_