Moved JsonPrefStore to use SequencedWorkerPool

chrome/browser/metrics/metrics_service.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.
 
 //------------------------------------------------------------------------------
 // Description of the life cycle of a instance of MetricsService.
 //
 //  OVERVIEW
 //
 // A MetricsService instance is typically created at application startup.  It
@@ skipping 1705 matching lines @@
   // Redundant setting to be sure we call for a clean shutdown.
   clean_shutdown_status_ = NEED_TO_SHUTDOWN;
 }
 
 bool MetricsService::UmaMetricsProperlyShutdown() {
   CHECK(clean_shutdown_status_ == CLEANLY_SHUTDOWN ||
         clean_shutdown_status_ == NEED_TO_SHUTDOWN);
   return clean_shutdown_status_ == CLEANLY_SHUTDOWN;
 }
 
-// For use in hack in LogCleanShutdown.
-static void Signal(base::WaitableEvent* event) {
-  event->Signal();
-}
-
 void MetricsService::LogCleanShutdown() {
   // Redundant hack to write pref ASAP.
   PrefService* pref = g_browser_process->local_state();
   pref->SetBoolean(prefs::kStabilityExitedCleanly, true);
   pref->CommitPendingWrite();
-  // Hack: TBD: Remove this wait.
-  // We are so concerned that the pref gets written, we are now willing to stall
-  // the UI thread until we get assurance that a pref-writing task has
-  // completed.
-  base::WaitableEvent done_writing(false, false);
-  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-                          base::Bind(Signal, &done_writing));
-  // http://crbug.com/124954
-  base::ThreadRestrictions::ScopedAllowWait allow_wait;
-  done_writing.TimedWait(base::TimeDelta::FromHours(1));
-
   // Redundant setting to assure that we always reset this value at shutdown
   // (and that we don't use some alternate path, and not call LogCleanShutdown).
   clean_shutdown_status_ = CLEANLY_SHUTDOWN;
 
   RecordBooleanPrefValue(prefs::kStabilityExitedCleanly, true);
 }
 
 #if defined(OS_CHROMEOS)
 void MetricsService::LogChromeOSCrash(const std::string &crash_type) {
   if (crash_type == "user")
@@ skipping 246 matching lines @@
   if (local_state) {
     const PrefService::Preference* uma_pref =
         local_state->FindPreference(prefs::kMetricsReportingEnabled);
     if (uma_pref) {
       bool success = uma_pref->GetValue()->GetAsBoolean(&result);
       DCHECK(success);
     }
   }
   return result;
 }