Convert --enable-md-history to a feature flag.

chrome/browser/ui/webui/uber/uber_ui.cc

Index: chrome/browser/ui/webui/uber/uber_ui.cc
diff --git a/chrome/browser/ui/webui/uber/uber_ui.cc b/chrome/browser/ui/webui/uber/uber_ui.cc
index 8b4159c3dda120a3c8301dc5202066c75b91fab0..34e67b12f6c3053e25dbc4a27939ebc4df0df56d 100644
--- a/chrome/browser/ui/webui/uber/uber_ui.cc
+++ b/chrome/browser/ui/webui/uber/uber_ui.cc
@@ -11,6 +11,7 @@
 #include "chrome/browser/ui/webui/extensions/extensions_ui.h"
 #include "chrome/browser/ui/webui/log_web_ui_url.h"
 #include "chrome/browser/ui/webui/options/options_ui.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/chrome_manifest_url_handlers.h"
 #include "chrome/common/url_constants.h"
@@ -108,8 +109,11 @@ content::WebUIDataSource* CreateUberFrameHTMLSource(
   bool overrides_history =
       HasExtensionType(browser_context, chrome::kChromeUIHistoryHost);
   source->AddString("overridesHistory", overrides_history ? "yes" : "no");
-  source->AddBoolean("hideHistory",
-                     ::switches::MdHistoryEnabled() && !overrides_history);
+  source->AddBoolean(
+      "hideHistory",
+      base::FeatureList::IsEnabled(features::kMaterialDesignHistoryFeature)
+      && !overrides_history);
+
   source->DisableDenyXFrameOptions();
   source->OverrideContentSecurityPolicyFrameSrc("frame-src chrome:;");