sync: Improve handling of bad UniquePos (retry)

sync/syncable/directory.cc

 // Copyright 2013 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 "sync/syncable/directory.h"
 
 #include <iterator>
 
 #include "base/base64.h"
 #include "base/debug/trace_event.h"
@@ skipping 149 matching lines @@
 
 DirOpenResult Directory::OpenImpl(
     const string& name,
     DirectoryChangeDelegate* delegate,
     const WeakHandle<TransactionObserver>&
         transaction_observer) {
   KernelLoadInfo info;
   // Temporary indices before kernel_ initialized in case Load fails. We 0(1)
   // swap these later.
   Directory::MetahandlesMap tmp_handles_map;
+
+  // Avoids mem leaks on failure.  Harmlessly deletes the empty hash map after
+  // the swap in the success case.
+  STLValueDeleter<Directory::MetahandlesMap> deleter(&tmp_handles_map);
+
   JournalIndex delete_journals;
 
   DirOpenResult result =
       store_->Load(&tmp_handles_map, &delete_journals, &info);
   if (OPENED != result)
     return result;
 
   kernel_ = new Kernel(name, info, delegate, transaction_observer);
   delete_journal_.reset(new DeleteJournal(&delete_journals));
   InitializeIndices(&tmp_handles_map);
@@ skipping 1242 matching lines @@
 
   for (OrderedChildSet::const_iterator i = children->begin();
        i != children->end(); ++i) {
     DCHECK_EQ(parent_id, (*i)->ref(PARENT_ID));
     result->push_back((*i)->ref(META_HANDLE));
   }
 }
 
 }  // namespace syncable
 }  // namespace syncer