chrome: Cleanup class/struct forward declarations

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 "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 BrowserThemePack;
 class ThemeSyncableService;
 class Profile;
 
 namespace base {
 class FilePath;
 }
 
 namespace color_utils {
 struct HSL;
 }
@@ skipping 289 matching lines @@
 
   BrowserThemeProvider original_theme_provider_;
   BrowserThemeProvider incognito_theme_provider_;
 
   base::WeakPtrFactory<ThemeService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThemeService);
 };
 
 #endif  // CHROME_BROWSER_THEMES_THEME_SERVICE_H_