Replace deprecated base::NonThreadSafe in chrome/browser/themes in favor of SequenceChecker.

chrome/browser/themes/theme_service.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_THEMES_THEME_SERVICE_H_
 #define CHROME_BROWSER_THEMES_THEME_SERVICE_H_
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/sequence_checker.h"
 #include "build/build_config.h"
 #include "chrome/common/features.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "extensions/features/features.h"
 #include "ui/base/theme_provider.h"
 
 class CustomThemeSupplier;
 class ThemeSyncableService;
@@ skipping 23 matching lines @@
 class ResourceBundle;
 }
 
 #ifdef __OBJC__
 @class NSString;
 // Sent whenever the browser theme changes.  Object => NSValue wrapping the
 // ThemeService that changed.
 extern "C" NSString* const kBrowserThemeDidChangeNotification;
 #endif  // __OBJC__
 
-class ThemeService : public base::NonThreadSafe,
-                     public content::NotificationObserver,
-                     public KeyedService {
+class ThemeService : public content::NotificationObserver, public KeyedService {
  public:
   // Public constants used in ThemeService and its subclasses:
   static const char kDefaultThemeID[];
 
   ThemeService();
   ~ThemeService() override;
 
   virtual void Init(Profile* profile);
 
   // KeyedService:
@@ skipping 246 matching lines @@
   std::unique_ptr<ThemeSyncableService> theme_syncable_service_;
 
 #if BUILDFLAG(ENABLE_EXTENSIONS)
   class ThemeObserver;
   std::unique_ptr<ThemeObserver> theme_observer_;
 #endif
 
   BrowserThemeProvider original_theme_provider_;
   BrowserThemeProvider incognito_theme_provider_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   base::WeakPtrFactory<ThemeService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThemeService);
 };
 
 #endif  // CHROME_BROWSER_THEMES_THEME_SERVICE_H_