components: Cleanup class/struct fwd declarations

components/sync_preferences/pref_service_syncable_factory.h

 // Copyright 2013 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 COMPONENTS_SYNC_PREFERENCES_PREF_SERVICE_SYNCABLE_FACTORY_H_
 #define COMPONENTS_SYNC_PREFERENCES_PREF_SERVICE_SYNCABLE_FACTORY_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/prefs/pref_service_factory.h"
 
-namespace base {
-class CommandLine;
-}
-
 namespace policy {
 class BrowserPolicyConnector;
 class PolicyService;
 }
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 namespace sync_preferences {
@@ skipping 24 matching lines @@
 
  private:
   PrefModelAssociatorClient* pref_model_associator_client_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefServiceSyncableFactory);
 };
 
 }  // namespace sync_preferences
 
 #endif  // COMPONENTS_SYNC_PREFERENCES_PREF_SERVICE_SYNCABLE_FACTORY_H_