[Sync] Split DirectoryChangeListener for thread-safety

chrome/browser/sync/engine/verify_updates_command.cc

Index: chrome/browser/sync/engine/verify_updates_command.cc
diff --git a/chrome/browser/sync/engine/verify_updates_command.cc b/chrome/browser/sync/engine/verify_updates_command.cc
index 2e907d04ca28dce4ed3e0e786f03efb5ae973008..672894aaf8d629fb3459a57ae89001fe2e5a76fb 100644
--- a/chrome/browser/sync/engine/verify_updates_command.cc
+++ b/chrome/browser/sync/engine/verify_updates_command.cc
@@ -5,6 +5,7 @@
 
 #include "chrome/browser/sync/engine/verify_updates_command.h"
 
+#include "base/tracked.h"
 #include "chrome/browser/sync/engine/syncer.h"
 #include "chrome/browser/sync/engine/syncer_proto_util.h"
 #include "chrome/browser/sync/engine/syncer_types.h"
@@ -35,7 +36,7 @@ void VerifyUpdatesCommand::ModelChangingExecuteImpl(
     LOG(ERROR) << "Scoped dir lookup failed!";
     return;
   }
-  WriteTransaction trans(dir, SYNCER, __FILE__, __LINE__);
+  WriteTransaction trans(dir, SYNCER, FROM_HERE);
   sessions::StatusController* status = session->status_controller();
   const GetUpdatesResponse& updates = status->updates_response().get_updates();
   int update_count = updates.entries().size();