[MD Settings] Add feature to enable md-settings by default.

chrome/browser/ui/chrome_pages.cc

 // 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.
 
 #include "chrome/browser/ui/chrome_pages.h"
 
 #include <stddef.h>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 197 matching lines @@
 void ShowPolicy(Browser* browser) {
   ShowSingletonTab(browser, GURL(kChromeUIPolicyURL));
 }
 
 void ShowSlow(Browser* browser) {
 #if defined(OS_CHROMEOS)
   ShowSingletonTab(browser, GURL(kChromeUISlowURL));
 #endif
 }
 
+std::string GetLegacySettingsHost() {
+  return kChromeUISettingsLegacyHost;
+}
+
+std::string GetMdSettingsHost() {
+  return kChromeUIMdSettingsHost;
+}
+
 GURL GetSettingsUrl(const std::string& sub_page) {
   std::string url = std::string(kChromeUISettingsURL) + sub_page;
 #if defined(OS_CHROMEOS)
   if (sub_page.find(kInternetOptionsSubPage, 0) != std::string::npos) {
     std::string::size_type loc = sub_page.find("?", 0);
     std::string network_page =
         loc != std::string::npos ? sub_page.substr(loc) : std::string();
     url = std::string(kChromeUISettingsURL) + network_page;
   }
 #endif
@@ skipping 165 matching lines @@
       SigninManagerFactory::GetForProfile(original_profile);
   DCHECK(manager->IsSigninAllowed());
   if (manager->IsAuthenticated())
     ShowSettings(browser);
   else
     ShowBrowserSignin(browser, access_point);
 }
 #endif
 
 }  // namespace chrome