[Sync] Replace ClearServerDataCallback with Closure.

components/sync/engine_impl/sync_manager_impl.cc

 // 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.
 
 #include "components/sync/engine_impl/sync_manager_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 977 matching lines @@
 
 bool SyncManagerImpl::HasDirectoryTypeDebugInfoObserver(
     TypeDebugInfoObserver* observer) {
   return model_type_registry_->HasDirectoryTypeDebugInfoObserver(observer);
 }
 
 void SyncManagerImpl::RequestEmitDebugInfo() {
   model_type_registry_->RequestEmitDebugInfo();
 }
 
-void SyncManagerImpl::ClearServerData(const ClearServerDataCallback& callback) {
+void SyncManagerImpl::ClearServerData(const base::Closure& callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
   scheduler_->Start(SyncScheduler::CLEAR_SERVER_DATA_MODE, base::Time());
   ClearParams params(callback);
   scheduler_->ScheduleClearServerData(params);
 }
 
 void SyncManagerImpl::OnCookieJarChanged(bool account_mismatch,
                                          bool empty_jar) {
   DCHECK(thread_checker_.CalledOnValidThread());
   cycle_context_->set_cookie_jar_mismatch(account_mismatch);
   cycle_context_->set_cookie_jar_empty(empty_jar);
 }
 
 void SyncManagerImpl::OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd) {
   directory()->OnMemoryDump(pmd);
 }
 
 }  // namespace syncer