Avoid useless SYNC_CYCLE_CONTINUATION sync cycle

chrome/browser/sync/engine/post_commit_message_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/post_commit_message_command.h"
 
 #include <vector>
 
 #include "base/location.h"
 #include "chrome/browser/sync/engine/syncer_proto_util.h"
 #include "chrome/browser/sync/engine/syncproto.h"
 #include "chrome/browser/sync/sessions/sync_session.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 
 using std::vector;
 
 namespace browser_sync {
 
 PostCommitMessageCommand::PostCommitMessageCommand() {}
 PostCommitMessageCommand::~PostCommitMessageCommand() {}
 
-void PostCommitMessageCommand::ExecuteImpl(sessions::SyncSession* session) {
+SyncerError PostCommitMessageCommand::ExecuteImpl(
+    sessions::SyncSession* session) {
   if (session->status_controller().commit_ids().empty())
-    return;  // Nothing to commit.
+    return NO_ERROR;  // Nothing to commit.
   ClientToServerResponse response;
   syncable::ScopedDirLookup dir(session->context()->directory_manager(),
                                 session->context()->account_name());
   if (!dir.good())
-    return;
+    return DIRECTORY_LOOKUP_FAILED;
   sessions::StatusController* status = session->mutable_status_controller();
-  if (!SyncerProtoUtil::PostClientToServerMessage(status->commit_message(),
-          &response, session)) {
+  SyncerError result = SyncerProtoUtil::PostClientToServerMessage(
+      status->commit_message(), &response, session);
+  if (result != NO_ERROR) {
     // None of our changes got through.  Clear the SYNCING bit which was
     // set to true during BuildCommitCommand, and which may still be true.
     // Not to be confused with IS_UNSYNCED, this bit is used to detect local
     // changes to items that happen during the server Commit operation.
     status->increment_num_consecutive_errors();
     syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);
     const vector<syncable::Id>& commit_ids = status->commit_ids();
     for (size_t i = 0; i < commit_ids.size(); i++) {
       syncable::MutableEntry entry(&trans, syncable::GET_BY_ID, commit_ids[i]);
       entry.Put(syncable::SYNCING, false);
     }
-    return;
-  } else {
-    status->set_items_committed();
+    return result;
   }
+
+  status->set_items_committed();
   status->mutable_commit_response()->CopyFrom(response);
+  return NO_ERROR;
 }
 
 }  // namespace browser_sync