[SyncFS] Make GetOriginStatusMap asynchronous

chrome/browser/sync_file_system/drive_backend/sync_worker.cc

 // Copyright 2014 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/drive_backend/sync_worker.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 186 matching lines @@
   context_->SetRemoteChangeProcessor(remote_change_processor_on_worker);
 }
 
 RemoteServiceState SyncWorker::GetCurrentState() const {
   if (!sync_enabled_)
     return REMOTE_SERVICE_DISABLED;
   return service_state_;
 }
 
 void SyncWorker::GetOriginStatusMap(
-    RemoteFileSyncService::OriginStatusMap* status_map) {
-  DCHECK(status_map);
+    const RemoteFileSyncService::StatusMapCallback& callback) {
+  RemoteFileSyncService::OriginStatusMap status_map;
 
   if (!GetMetadataDatabase())
     return;
 
   std::vector<std::string> app_ids;
   GetMetadataDatabase()->GetRegisteredAppIDs(&app_ids);
 
   for (std::vector<std::string>::const_iterator itr = app_ids.begin();
        itr != app_ids.end(); ++itr) {
     const std::string& app_id = *itr;
-    GURL origin =
-        extensions::Extension::GetBaseURLFromExtensionId(app_id);
-    (*status_map)[origin] =
-        GetMetadataDatabase()->IsAppEnabled(app_id) ?
+    GURL origin = extensions::Extension::GetBaseURLFromExtensionId(app_id);
+    status_map[origin] = GetMetadataDatabase()->IsAppEnabled(app_id) ?
         "Enabled" : "Disabled";
   }
+
+  callback.Run(status_map);
 }
 
 scoped_ptr<base::ListValue> SyncWorker::DumpFiles(const GURL& origin) {
   if (!GetMetadataDatabase())
     return scoped_ptr<base::ListValue>();
   return GetMetadataDatabase()->DumpFiles(origin.host());
 }
 
 scoped_ptr<base::ListValue> SyncWorker::DumpDatabase() {
   if (!GetMetadataDatabase())
@@ skipping 471 matching lines @@
             "Service state changed: %d->%d: %s",
             old_state, GetCurrentState(), description.c_str());
 
   FOR_EACH_OBSERVER(
       Observer, observers_,
       UpdateServiceState(GetCurrentState(), description));
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system