[Sync] Replace ClearServerDataCallback with Closure.

components/sync/driver/glue/sync_backend_host_core.cc

 // 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.
 
 #include "components/sync/driver/glue/sync_backend_host_core.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
@@ skipping 558 matching lines @@
       FROM_HERE, base::TimeDelta::FromSeconds(kSaveChangesIntervalSeconds),
       this, &SyncBackendHostCore::SaveChanges);
 }
 
 void SyncBackendHostCore::SaveChanges() {
   DCHECK(thread_checker_.CalledOnValidThread());
   sync_manager_->SaveChanges();
 }
 
 void SyncBackendHostCore::DoClearServerData(
-    const SyncManager::ClearServerDataCallback& frontend_callback) {
+    const base::Closure& frontend_callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  const SyncManager::ClearServerDataCallback callback =
+  const base::Closure callback =
       base::Bind(&SyncBackendHostCore::ClearServerDataDone,
                  weak_ptr_factory_.GetWeakPtr(), frontend_callback);
   sync_manager_->ClearServerData(callback);
 }
 
 void SyncBackendHostCore::DoOnCookieJarChanged(bool account_mismatch,
                                                bool empty_jar,
                                                const base::Closure& callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
   sync_manager_->OnCookieJarChanged(account_mismatch, empty_jar);
   if (!callback.is_null()) {
     host_.Call(FROM_HERE,
                &SyncBackendHostImpl::OnCookieJarChangedDoneOnFrontendLoop,
                callback);
   }
 }
 
 void SyncBackendHostCore::ClearServerDataDone(
     const base::Closure& frontend_callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
   host_.Call(FROM_HERE, &SyncBackendHostImpl::ClearServerDataDoneOnFrontendLoop,
              frontend_callback);
 }
 
 }  // namespace syncer