components: Cleanup class/struct fwd declarations

components/autofill/core/browser/webdata/autofill_wallet_metadata_syncable_service.h

 // Copyright 2015 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_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_WALLET_METADATA_SYNCABLE_SERVICE_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_WALLET_METADATA_SYNCABLE_SERVICE_H_
 
 #include <memory>
 #include <string>
 
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/scoped_observer.h"
 #include "base/supports_user_data.h"
 #include "base/threading/thread_checker.h"
 #include "components/autofill/core/browser/webdata/autofill_change.h"
 #include "components/autofill/core/browser/webdata/autofill_webdata_service_observer.h"
 #include "components/sync/model/sync_error.h"
 #include "components/sync/model/sync_merge_result.h"
 #include "components/sync/model/syncable_service.h"
 #include "components/sync/protocol/autofill_specifics.pb.h"
 
 namespace base {
 template <typename, typename>
 class ScopedPtrHashMap;
 }
 
 namespace syncer {
 class SyncChangeProcessor;
-class SyncData;
 class SyncErrorFactory;
 }
 
 namespace tracked_objects {
 class Location;
 }
 
 namespace autofill {
 
 class AutofillDataModel;
@@ skipping 102 matching lines @@
 
   // Local metadata plus metadata for the data that hasn't synced down yet.
   syncer::SyncDataList cache_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillWalletMetadataSyncableService);
 };
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_WALLET_METADATA_SYNCABLE_SERVICE_H_