bookmarks: Forward declare DefaultSingletonTraits in bookmark_model_factory.h

chrome/browser/bookmarks/bookmark_model_factory.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_BOOKMARKS_BOOKMARK_MODEL_FACTORY_H_
 #define CHROME_BROWSER_BOOKMARKS_BOOKMARK_MODEL_FACTORY_H_
 
-#include "base/memory/singleton.h"
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
+template <typename T> struct DefaultSingletonTraits;
+
 class Profile;
 class BookmarkModel;
 
 // Singleton that owns all BookmarkModel and associates them with
 // Profiles.
 class BookmarkModelFactory : public ProfileKeyedServiceFactory {
  public:
   static BookmarkModel* GetForProfile(Profile* profile);
 
   static BookmarkModel* GetForProfileIfExists(Profile* profile);
 
   static BookmarkModelFactory* GetInstance();
 
  private:
   friend struct DefaultSingletonTraits<BookmarkModelFactory>;
 
   BookmarkModelFactory();
   virtual ~BookmarkModelFactory();
 
   // ProfileKeyedServiceFactory:
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       Profile* profile) const OVERRIDE;
   virtual void RegisterUserPrefs(PrefService* user_prefs) OVERRIDE;
   virtual bool ServiceRedirectedInIncognito() OVERRIDE;
   virtual bool ServiceIsNULLWhileTesting() OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(BookmarkModelFactory);
 };
 
 #endif  // CHROME_BROWSER_BOOKMARKS_BOOKMARK_MODEL_FACTORY_H_