[Sync] Split DirectoryChangeListener for thread-safety

chrome/browser/sync/engine/process_commit_response_command.cc

Index: chrome/browser/sync/engine/process_commit_response_command.cc
diff --git a/chrome/browser/sync/engine/process_commit_response_command.cc b/chrome/browser/sync/engine/process_commit_response_command.cc
index 53be5395bf614c0f084352186918a964f1c5194a..bffda7d6a4a8edbd5b7f15237a9a42e848466680 100644
--- a/chrome/browser/sync/engine/process_commit_response_command.cc
+++ b/chrome/browser/sync/engine/process_commit_response_command.cc
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/tracked.h"
 #include "chrome/browser/sync/engine/syncer_proto_util.h"
 #include "chrome/browser/sync/engine/syncer_util.h"
 #include "chrome/browser/sync/engine/syncproto.h"
@@ -136,7 +137,7 @@ void ProcessCommitResponseCommand::ProcessCommitResponse(
   ConflictProgress* conflict_progress = status->mutable_conflict_progress();
   OrderedCommitSet::Projection proj = status->commit_id_projection();
   if (!proj.empty()) { // Scope for WriteTransaction.
-    WriteTransaction trans(dir, SYNCER, __FILE__, __LINE__);
+    WriteTransaction trans(dir, SYNCER, FROM_HERE);
     for (size_t i = 0; i < proj.size(); i++) {
       CommitResponse::ResponseType response_type =
           ProcessSingleCommitResponse(&trans, cr.entryresponse(proj[i]),