Remove the enable_themes build flag and define.

chrome/browser/ui/webui/signin/md_user_manager_ui.cc

 // Copyright 2016 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/webui/signin/md_user_manager_ui.h"
 
 #include <string>
 
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 30 matching lines @@
   web_ui->AddMessageHandler(signin_supervised_user_import_handler_);
 #endif
 
   base::DictionaryValue localized_strings;
   GetLocalizedStrings(&localized_strings);
 
   Profile* profile = Profile::FromWebUI(web_ui);
   // Set up the chrome://md-user-manager/ source.
   content::WebUIDataSource::Add(profile, CreateUIDataSource(localized_strings));
 
-#if defined(ENABLE_THEMES)
   // Set up the chrome://theme/ source
   ThemeSource* theme = new ThemeSource(profile);
   content::URLDataSource::Add(profile, theme);
-#endif
 }
 
 MDUserManagerUI::~MDUserManagerUI() {}
 
 content::WebUIDataSource* MDUserManagerUI::CreateUIDataSource(
     const base::DictionaryValue& localized_strings) {
   content::WebUIDataSource* source =
       content::WebUIDataSource::Create(chrome::kChromeUIMdUserManagerHost);
   source->AddLocalizedStrings(localized_strings);
   source->AddBoolean("profileShortcutsEnabled",
@@ skipping 56 matching lines @@
 #endif
   const std::string& app_locale = g_browser_process->GetApplicationLocale();
   webui::SetLoadTimeDataDefaults(app_locale, localized_strings);
 
 #if defined(GOOGLE_CHROME_BUILD)
   localized_strings->SetString("buildType", "chrome");
 #else
   localized_strings->SetString("buildType", "chromium");
 #endif
 }