[Sync] Split DirectoryChangeListener for thread-safety

chrome/browser/sync/engine/syncer_util.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_util.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 #include <vector>
 
+#include "base/tracked.h"
 #include "chrome/browser/sync/engine/conflict_resolver.h"
 #include "chrome/browser/sync/engine/syncer_proto_util.h"
 #include "chrome/browser/sync/engine/syncer_types.h"
 #include "chrome/browser/sync/engine/syncproto.h"
 #include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
 #include "chrome/browser/sync/protocol/nigori_specifics.pb.h"
 #include "chrome/browser/sync/protocol/password_specifics.pb.h"
 #include "chrome/browser/sync/protocol/sync.pb.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 #include "chrome/browser/sync/syncable/model_type.h"
@@ skipping 630 matching lines @@
   // 1. Scan deleted unsynced entries looking up their pre-delete tree for any
   //    of the deleted folders.
   // 2. Take each folder and do a tree walk of all entries underneath it.
   // #2 has a lower big O cost, but writing code to limit the time spent inside
   // the transaction during each step is simpler with 1. Changing this decision
   // may be sensible if this code shows up in profiling.
   if (deleted_folders->empty())
     return;
   Directory::UnsyncedMetaHandles handles;
   {
-    ReadTransaction trans(dir, __FILE__, __LINE__);
+    ReadTransaction trans(dir, FROM_HERE);
     dir->GetUnsyncedMetaHandles(&trans, &handles);
   }
   if (handles.empty())
     return;
   Directory::UnsyncedMetaHandles::iterator it;
   for (it = handles.begin() ; it != handles.end() ; ++it) {
     // Single transaction / entry we deal with.
-    WriteTransaction trans(dir, SYNCER, __FILE__, __LINE__);
+    WriteTransaction trans(dir, SYNCER, FROM_HERE);
     MutableEntry entry(&trans, GET_BY_HANDLE, *it);
     if (!entry.Get(IS_UNSYNCED) || !entry.Get(IS_DEL))
       continue;
     syncable::Id id = entry.Get(PARENT_ID);
     while (id != trans.root_id()) {
       if (deleted_folders->find(id) != deleted_folders->end()) {
         // We've synced the deletion of this deleted entries parent.
         entry.Put(IS_UNSYNCED, false);
         break;
       }
@@ skipping 139 matching lines @@
   if (update.version() < target->Get(SERVER_VERSION)) {
     LOG(WARNING) << "Update older than current server version for "
                  << *target << " Update:"
                  << SyncerProtoUtil::SyncEntityDebugString(update);
     return VERIFY_SUCCESS;  // Expected in new sync protocol.
   }
   return VERIFY_UNDECIDED;
 }
 
 }  // namespace browser_sync