components: Cleanup class/struct fwd declarations

components/content_settings/core/browser/host_content_settings_map.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.
 
 // Maps hostnames to custom content settings.  Written on the UI thread and read
 // on any thread.  One instance per profile.
 
 #ifndef COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_
 #define COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread_checker.h"
 #include "components/content_settings/core/browser/content_settings_observer.h"
 #include "components/content_settings/core/browser/content_settings_utils.h"
 #include "components/content_settings/core/common/content_settings.h"
 #include "components/content_settings/core/common/content_settings_pattern.h"
 #include "components/content_settings/core/common/content_settings_types.h"
 #include "components/keyed_service/core/refcounted_keyed_service.h"
 #include "components/prefs/pref_change_registrar.h"
 
-class ExtensionService;
 class GURL;
 class PrefService;
 
 namespace base {
 class Clock;
 class Value;
 }
 
 namespace content_settings {
 class ObservableProvider;
 class ProviderInterface;
 class PrefProvider;
+class RuleIterator;
 class TestUtils;
 }
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 class HostContentSettingsMap : public content_settings::Observer,
                                public RefcountedKeyedService {
  public:
@@ skipping 357 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::ObserverList<content_settings::Observer> observers_;
 
   base::WeakPtrFactory<HostContentSettingsMap> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HostContentSettingsMap);
 };
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_