[Sync] Replace ClearServerDataCallback with Closure.

components/sync/driver/glue/sync_backend_host_core.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_DRIVER_GLUE_SYNC_BACKEND_HOST_CORE_H_
 #define COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_HOST_CORE_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
+#include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "base/trace_event/memory_dump_provider.h"
 #include "components/invalidation/public/invalidation.h"
 #include "components/sync/base/cancelation_signal.h"
 #include "components/sync/base/system_encryptor.h"
 #include "components/sync/driver/glue/sync_backend_host_impl.h"
@@ skipping 129 matching lines @@
   void EnableDirectoryTypeDebugInfoForwarding();
 
   // Disables forwarding of directory type debug counters.
   void DisableDirectoryTypeDebugInfoForwarding();
 
   // Tell the sync manager to persist its state by writing to disk.
   // Called on the sync thread, both by a timer and, on Android, when the
   // application is backgrounded.
   void SaveChanges();
 
-  void DoClearServerData(
-      const SyncManager::ClearServerDataCallback& frontend_callback);
+  void DoClearServerData(const base::Closure& frontend_callback);
 
   // Notify the syncer that the cookie jar has changed.
   void DoOnCookieJarChanged(bool account_mismatch,
                             bool empty_jar,
                             const base::Closure& callback);
 
  private:
   friend class base::RefCountedThreadSafe<SyncBackendHostCore>;
 
   ~SyncBackendHostCore() override;
@@ skipping 58 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<SyncBackendHostCore> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHostCore);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_HOST_CORE_H_