Make file IO occur on the right thread.

chrome/browser/chromeos/system/timezone_settings.cc

 // Copyright (c) 2011 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/chromeos/system/timezone_settings.h"
 
+#include "base/bind.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/observer_list.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
+#include "content/browser/browser_thread.h"
 
 namespace chromeos {
 namespace system {
 
 namespace {
 
 // The filepath to the timezone file that symlinks to the actual timezone file.
 const char kTimezoneSymlink[] = "/var/lib/timezone/localtime";
 const char kTimezoneSymlink2[] = "/var/lib/timezone/localtime2";
 
@@ skipping 88 matching lines @@
   return *timezone_.get();
 }
 
 void TimezoneSettingsImpl::SetTimezone(const icu::TimeZone& timezone) {
   timezone_.reset(timezone.clone());
   icu::UnicodeString unicode;
   timezone.getID(unicode);
   std::string id;
   UTF16ToUTF8(unicode.getBuffer(), unicode.length(), &id);
   VLOG(1) << "Setting timezone to " << id;
-  SetTimezoneIDFromString(id);
+  // Change the timezone config files on the FILE thread. It's safe to do this
+  // in the background as the following operations don't depend on the
+  // completion of the config change.
+  BrowserThread::PostTask(BrowserThread::FILE,
+                          FROM_HERE,
+                          base::Bind(&SetTimezoneIDFromString, id));
   icu::TimeZone::setDefault(timezone);
   FOR_EACH_OBSERVER(Observer, observers_, TimezoneChanged(timezone));
 }
 
 void TimezoneSettingsImpl::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void TimezoneSettingsImpl::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
@@ skipping 21 matching lines @@
 TimezoneSettings* TimezoneSettings::GetInstance() {
   return TimezoneSettingsImpl::GetInstance();
 }
 
 }  // namespace system
 }  // namespace chromeos
 
 // Allows InvokeLater without adding refcounting. TimezoneSettingsImpl is a
 // Singleton and won't be deleted until it's last InvokeLater is run.
 DISABLE_RUNNABLE_METHOD_REFCOUNT(chromeos::system::TimezoneSettingsImpl);