Avoid useless SYNC_CYCLE_CONTINUATION sync cycle

chrome/browser/sync/engine/download_updates_command.cc

Index: chrome/browser/sync/engine/download_updates_command.cc
diff --git a/chrome/browser/sync/engine/download_updates_command.cc b/chrome/browser/sync/engine/download_updates_command.cc
index 86414a6e1e2ce26a4ca93c306a6f83af2bfd3fcb..c2de03fcad967a283dc04838fd4719ff83cca5e2 100644
--- a/chrome/browser/sync/engine/download_updates_command.cc
+++ b/chrome/browser/sync/engine/download_updates_command.cc
@@ -30,7 +30,7 @@ using syncable::ModelTypeSetToString;
 DownloadUpdatesCommand::DownloadUpdatesCommand() {}
 DownloadUpdatesCommand::~DownloadUpdatesCommand() {}
 
-void DownloadUpdatesCommand::ExecuteImpl(SyncSession* session) {
+SyncerError DownloadUpdatesCommand::ExecuteImpl(SyncSession* session) {
   ClientToServerMessage client_to_server_message;
   ClientToServerResponse update_response;
 
@@ -48,7 +48,7 @@ void DownloadUpdatesCommand::ExecuteImpl(SyncSession* session) {
                       session->context()->account_name());
   if (!dir.good()) {
     LOG(ERROR) << "Scoped dir lookup failed!";
-    return;
+    return DIRECTORY_LOOKUP_FAILED;
   }
 
   // Request updates for all enabled types.
@@ -91,7 +91,7 @@ void DownloadUpdatesCommand::ExecuteImpl(SyncSession* session) {
 
   AppendClientDebugInfoIfNeeded(session, debug_info);
 
-  bool ok = SyncerProtoUtil::PostClientToServerMessage(
+  SyncerError result = SyncerProtoUtil::PostClientToServerMessage(
       client_to_server_message,
       &update_response,
       session);
@@ -101,11 +101,11 @@ void DownloadUpdatesCommand::ExecuteImpl(SyncSession* session) {
 
   StatusController* status = session->mutable_status_controller();
   status->set_updates_request_types(enabled_types);
-  if (!ok) {
+  if (result != NO_ERROR) {
     status->increment_num_consecutive_errors();
     status->mutable_updates_response()->Clear();
     LOG(ERROR) << "PostClientToServerMessage() failed during GetUpdates";
-    return;
+    return result;
   }
 
   status->mutable_updates_response()->CopyFrom(update_response);
@@ -115,6 +115,7 @@ void DownloadUpdatesCommand::ExecuteImpl(SyncSession* session) {
            << " updates and indicated "
            << update_response.get_updates().changes_remaining()
            << " updates left on server.";
+  return result;
 }
 
 void DownloadUpdatesCommand::AppendClientDebugInfoIfNeeded(