components: Cleanup class/struct fwd declarations

components/sync/syncable/base_node.h

 // Copyright 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 COMPONENTS_SYNC_SYNCABLE_BASE_NODE_H_
 #define COMPONENTS_SYNC_SYNCABLE_BASE_NODE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/model/attachments/attachment.h"
 #include "components/sync/protocol/sync.pb.h"
 #include "url/gurl.h"
 
 // Forward declarations of internal class types so that sync API objects
 // may have opaque pointers to these types.
 namespace base {
 class DictionaryValue;
 }
 
 namespace sync_pb {
-class AppSpecifics;
-class AutofillSpecifics;
-class AutofillProfileSpecifics;
 class BookmarkSpecifics;
 class EntitySpecifics;
-class ExtensionSpecifics;
-class SessionSpecifics;
 class NigoriSpecifics;
-class PreferenceSpecifics;
 class PasswordSpecificsData;
-class ThemeSpecifics;
 class TypedUrlSpecifics;
 }  // namespace sync_pb
 
 namespace syncer {
 
 class BaseTransaction;
 
 namespace syncable {
 class BaseTransaction;
 class Entry;
@@ skipping 183 matching lines @@
 
   // Same as |unencrypted_data_|, but for legacy password encryption.
   std::unique_ptr<sync_pb::PasswordSpecificsData> password_data_;
 
   DISALLOW_COPY_AND_ASSIGN(BaseNode);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_SYNCABLE_BASE_NODE_H_