Add tracing to prefs for analyzing startup performance

chrome/browser/prefs/chrome_pref_service_factory.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 "chrome/browser/prefs/chrome_pref_service_factory.h"
 
 #include "base/bind.h"
+#include "base/debug/trace_event.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/default_pref_store.h"
 #include "base/prefs/json_pref_store.h"
 #include "base/prefs/pref_notifier_impl.h"
 #include "base/prefs/pref_registry.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/pref_value_store.h"
 #include "chrome/browser/policy/configuration_policy_pref_store.h"
@@ skipping 93 matching lines @@
   return builder.Create(pref_registry);
 }
 
 PrefServiceSyncable* CreateProfilePrefs(
     const base::FilePath& pref_filename,
     base::SequencedTaskRunner* pref_io_task_runner,
     policy::PolicyService* policy_service,
     const scoped_refptr<PrefStore>& extension_prefs,
     const scoped_refptr<user_prefs::PrefRegistrySyncable>& pref_registry,
     bool async) {
+  TRACE_EVENT0("browser", "chrome_prefs::CreateProfilePrefs")
   PrefServiceSyncableBuilder builder;
   PrepareBuilder(&builder,
                  pref_filename,
                  pref_io_task_runner,
                  policy_service,
                  extension_prefs,
                  async);
   return builder.CreateSyncable(pref_registry);
 }
 
 }  // namespace chrome_prefs