Avoid useless SYNC_CYCLE_CONTINUATION sync cycle

chrome/browser/sync/engine/apply_updates_command.cc

 // Copyright (c) 2011 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/engine/apply_updates_command.h"
 
 #include "base/location.h"
 #include "chrome/browser/sync/engine/update_applicator.h"
 #include "chrome/browser/sync/sessions/sync_session.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
@@ skipping 26 matching lines @@
 
   for (syncable::FullModelTypeSet::Iterator it =
            server_types_with_unapplied_updates.First(); it.Good(); it.Inc()) {
     groups_with_unapplied_updates.insert(
         GetGroupForModelType(it.Get(), session.routing_info()));
   }
 
   return groups_with_unapplied_updates;
 }
 
-void ApplyUpdatesCommand::ModelChangingExecuteImpl(SyncSession* session) {
+SyncerError ApplyUpdatesCommand::ModelChangingExecuteImpl(
+    SyncSession* session) {
   syncable::ScopedDirLookup dir(session->context()->directory_manager(),
                                 session->context()->account_name());
   if (!dir.good()) {
     LOG(ERROR) << "Scoped dir lookup failed!";
-    return;
+    return DIRECTORY_LOOKUP_FAILED;
   }
 
   syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);
 
   // Compute server types with unapplied updates that fall under our
   // group restriction.
   const syncable::FullModelTypeSet server_types_with_unapplied_updates =
       dir->GetServerTypesWithUnappliedUpdates(&trans);
   syncable::FullModelTypeSet server_type_restriction;
   for (syncable::FullModelTypeSet::Iterator it =
@@ skipping 21 matching lines @@
   // This might be the first time we've fully completed a sync cycle, for
   // some subset of the currently synced datatypes.
   const sessions::StatusController& status(session->status_controller());
   if (status.ServerSaysNothingMoreToDownload()) {
     for (syncable::ModelTypeSet::Iterator it =
              status.updates_request_types().First(); it.Good(); it.Inc()) {
       // This gets persisted to the directory's backing store.
       dir->set_initial_sync_ended_for_type(it.Get(), true);
     }
   }
+
+  return NO_ERROR;
 }
 
 }  // namespace browser_sync