Fix a race condition in preference metric reporting.

base/prefs/pref_service_builder.cc

 // Copyright (c) 2012 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 "base/prefs/pref_service_builder.h"
 
 #include "base/bind.h"
 #include "base/prefs/default_pref_store.h"
 #include "base/prefs/json_pref_store.h"
+#include "base/prefs/pref_filter.h"
 #include "base/prefs/pref_notifier_impl.h"
 #include "base/prefs/pref_service.h"
 
 #include "base/prefs/pref_value_store.h"
 
 namespace {
 
 // Do-nothing default implementation.
 void DoNothingHandleReadError(PersistentPrefStore::PrefReadError error) {
 }
@@ skipping 42 matching lines @@
 PrefServiceBuilder& PrefServiceBuilder::WithReadErrorCallback(
     const base::Callback<void(PersistentPrefStore::PrefReadError)>&
     read_error_callback) {
   read_error_callback_ = read_error_callback;
   return *this;
 }
 
 PrefServiceBuilder& PrefServiceBuilder::WithUserFilePrefs(
     const base::FilePath& prefs_file,
     base::SequencedTaskRunner* task_runner) {
-  user_prefs_ = new JsonPrefStore(prefs_file, task_runner);
+  user_prefs_ = new JsonPrefStore(prefs_file,
+                                  task_runner,
+                                  scoped_ptr<PrefFilter>());
   return *this;
 }
 
 PrefServiceBuilder& PrefServiceBuilder::WithAsync(bool async) {
   async_ = async;
   return *this;
 }
 
 PrefService* PrefServiceBuilder::Create(PrefRegistry* pref_registry) {
   PrefNotifierImpl* pref_notifier = new PrefNotifierImpl();
@@ skipping 18 matching lines @@
 void PrefServiceBuilder::ResetDefaultState() {
   managed_prefs_ = NULL;
   supervised_user_prefs_ = NULL;
   extension_prefs_ = NULL;
   command_line_prefs_ = NULL;
   user_prefs_ = NULL;
   recommended_prefs_ = NULL;
   read_error_callback_ = base::Bind(&DoNothingHandleReadError);
   async_ = false;
 }