Detect & destroy dead conflictresolver paths.

chrome/browser/sync/engine/conflict_resolver.h

 // 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.
 //
 // A class that watches the syncer and attempts to resolve any conflicts that
 // occur.
 
 #ifndef CHROME_BROWSER_SYNC_ENGINE_CONFLICT_RESOLVER_H_
 #define CHROME_BROWSER_SYNC_ENGINE_CONFLICT_RESOLVER_H_
 #pragma once
@@ skipping 69 matching lines @@
   // Returns true if we're stuck.
   template <typename InputIt>
   bool LogAndSignalIfConflictStuck(syncable::BaseTransaction* trans,
                                    int attempt_count,
                                    InputIt start, InputIt end,
                                    sessions::StatusController* status);
 
   ConflictSetCountMap conflict_set_count_map_;
   SimpleConflictCountMap simple_conflict_count_map_;
 
-  // Contains the ids of uncommitted items that are children of entries merged
-  // in the previous cycle. This is used to speed up the merge resolution of
-  // deep trees. Used to happen in store refresh.
-  // TODO(chron): Can we get rid of this optimization?
-  std::set<syncable::Id> children_of_merged_dirs_;
-
   DISALLOW_COPY_AND_ASSIGN(ConflictResolver);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_CONFLICT_RESOLVER_H_