[Sync] Split DirectoryChangeListener for thread-safety

chrome/browser/sync/engine/syncer.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/syncer.h"
 
 #include "base/message_loop.h"
 #include "base/time.h"
+#include "base/tracked.h"
 #include "chrome/browser/sync/engine/apply_updates_command.h"
 #include "chrome/browser/sync/engine/build_and_process_conflict_sets_command.h"
 #include "chrome/browser/sync/engine/build_commit_command.h"
 #include "chrome/browser/sync/engine/cleanup_disabled_types_command.h"
 #include "chrome/browser/sync/engine/clear_data_command.h"
 #include "chrome/browser/sync/engine/conflict_resolver.h"
 #include "chrome/browser/sync/engine/download_updates_command.h"
 #include "chrome/browser/sync/engine/get_commit_ids_command.h"
 #include "chrome/browser/sync/engine/net/server_connection_manager.h"
 #include "chrome/browser/sync/engine/post_commit_message_command.h"
@@ skipping 141 matching lines @@
       case BUILD_COMMIT_REQUEST: {
         session->status_controller()->set_syncing(true);
 
         VLOG(1) << "Processing Commit Request";
         ScopedDirLookup dir(session->context()->directory_manager(),
                             session->context()->account_name());
         if (!dir.good()) {
           LOG(ERROR) << "Scoped dir lookup failed!";
           return;
         }
-        WriteTransaction trans(dir, SYNCER, __FILE__, __LINE__);
+        WriteTransaction trans(dir, SYNCER, FROM_HERE);
         sessions::ScopedSetSessionWriteTransaction set_trans(session, &trans);
 
         VLOG(1) << "Getting the Commit IDs";
         GetCommitIdsCommand get_commit_ids_command(
             session->context()->max_commit_batch_size());
         get_commit_ids_command.Execute(session);
 
         if (!session->status_controller()->commit_ids().empty()) {
           VLOG(1) << "Building a commit message";
           BuildCommitCommand build_commit_command;
@@ skipping 148 matching lines @@
   entry->Put(SERVER_CTIME, 0);
   entry->Put(SERVER_VERSION, 0);
   entry->Put(SERVER_IS_DIR, false);
   entry->Put(SERVER_IS_DEL, false);
   entry->Put(IS_UNAPPLIED_UPDATE, false);
   entry->Put(SERVER_SPECIFICS, sync_pb::EntitySpecifics::default_instance());
   entry->Put(SERVER_POSITION_IN_PARENT, 0);
 }
 
 }  // namespace browser_sync