Fix test failure on Cronet Asan bot

components/cronet/host_cache_persistence_manager.cc

 // Copyright 2017 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 "components/cronet/host_cache_persistence_manager.h"
 
 #include <memory>
 
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
 #include "components/prefs/pref_service.h"
 
 namespace cronet {
 
 HostCachePersistenceManager::HostCachePersistenceManager(
     net::HostCache* cache,
     PrefService* pref_service,
     std::string pref_name,
     base::TimeDelta delay)
     : cache_(cache),
       pref_service_(pref_service),
       pref_name_(pref_name),
+      writing_pref_(false),
       delay_(delay),
       weak_factory_(this) {
   DCHECK(cache_);
   DCHECK(pref_service_);
 
   // Get the initial value of the pref if it's already initialized.
   if (pref_service_->HasPrefPath(pref_name_))
     ReadFromDisk();
 
   registrar_.Init(pref_service_);
@@ skipping 36 matching lines @@
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   base::ListValue value;
   cache_->GetAsListValue(&value, false);
   writing_pref_ = true;
   pref_service_->Set(pref_name_, value);
   writing_pref_ = false;
 }
 
 }  // namespace cronet