Enables MD User Manager by default

components/signin/core/common/signin_switches.cc

 // Copyright 2014 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 "components/signin/core/common/signin_switches.h"
 
 namespace switches {
 
 // Clears the token service before using it. This allows simulating the
 // expiration of credentials during testing.
@@ skipping 18 matching lines @@
 extern const char kEnableRefreshTokenAnnotationRequest[] =
     "enable-refresh-token-annotation-request";
 
 // Enables multiple account versions of chrome.identity APIs.
 const char kExtensionsMultiAccount[] = "extensions-multi-account";
 
 // Enables using GAIA information to populate profile name and icon.
 const char kGoogleProfileInfo[] = "google-profile-info";
 
 const base::Feature kMaterialDesignUserManager {
-  "MaterialDesignUserManager", base::FEATURE_DISABLED_BY_DEFAULT
+  "MaterialDesignUserManager", base::FEATURE_ENABLED_BY_DEFAULT
 };
 
 // Enables or disables the material design desktop user menu.
 const base::Feature kMaterialDesignUserMenu {
   "MaterialDesignUserMenu", base::FEATURE_DISABLED_BY_DEFAULT
 };
 
 // Enables or disables the new password separated sign in flow in a tab modal
 // dialog.
 const base::Feature kUsePasswordSeparatedSigninFlow {
   "UsePasswordSeparatedSigninFlow", base::FEATURE_ENABLED_BY_DEFAULT
 };
 
 }  // namespace switches