[SyncFS] Make DumpFiles async

chrome/browser/sync_file_system/mock_remote_file_sync_service.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 "chrome/browser/sync_file_system/mock_remote_file_sync_service.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 36 matching lines @@
   ON_CALL(*this, GetDefaultConflictResolutionPolicy())
       .WillByDefault(
           Invoke(this, &self::GetDefaultConflictResolutionPolicyStub));
   ON_CALL(*this, GetConflictResolutionPolicy(_))
       .WillByDefault(Invoke(this, &self::GetConflictResolutionPolicyStub));
 }
 
 MockRemoteFileSyncService::~MockRemoteFileSyncService() {
 }
 
-scoped_ptr<base::ListValue> MockRemoteFileSyncService::DumpFiles(
-    const GURL& origin) {
-  return scoped_ptr<base::ListValue>();
+void MockRemoteFileSyncService::DumpFiles(const GURL& origin,
+                                          const ListCallback& callback) {
+  callback.Run(scoped_ptr<base::ListValue>());
 }
 
 scoped_ptr<base::ListValue> MockRemoteFileSyncService::DumpDatabase() {
   return scoped_ptr<base::ListValue>();
 }
 
 void MockRemoteFileSyncService::SetServiceState(RemoteServiceState state) {
   state_ = state;
 }
 
@@ skipping 77 matching lines @@
 MockRemoteFileSyncService::GetConflictResolutionPolicyStub(
     const GURL& origin) const {
   return conflict_resolution_policy_;
 }
 
 RemoteServiceState MockRemoteFileSyncService::GetCurrentStateStub() const {
   return state_;
 }
 
 }  // namespace sync_file_system