1// Copyright 2014 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef CONTENT_BROWSER_TIME_ZONE_MONITOR_H_ 6#define CONTENT_BROWSER_TIME_ZONE_MONITOR_H_ 7 8#include "base/basictypes.h" 9#include "base/memory/scoped_ptr.h" 10 11namespace content { 12 13// TimeZoneMonitor watches the system time zone, and notifies renderers 14// when it changes. Some renderer code caches the system time zone, so 15// this notification is necessary to inform such code that cached 16// timezone data may have become invalid. Due to sandboxing, it is not 17// possible for renderer processes to monitor for system time zone 18// changes themselves, so this must happen in the browser process. 19// 20// Sandboxing also may prevent renderer processes from reading the time 21// zone when it does change, so platforms may have to deal with this in 22// platform-specific ways: 23// - Mac uses a sandbox hole defined in content/renderer/renderer.sb. 24// - Linux-based platforms use ProxyLocaltimeCallToBrowser in 25// content/zygote/zygote_main_linux.cc and HandleLocaltime in 26// content/browser/renderer_host/sandbox_ipc_linux.cc to override 27// localtime in renderer processes with custom code that calls 28// localtime in the browser process via Chrome IPC. 29 30class TimeZoneMonitor { 31 public: 32 // Returns a new TimeZoneMonitor object (likely a subclass) specific to the 33 // platform. 34 static scoped_ptr<TimeZoneMonitor> Create(); 35 36 virtual ~TimeZoneMonitor(); 37 38 protected: 39 TimeZoneMonitor(); 40 41 // Loop over all renderers and notify them that the system time zone may 42 // have changed. 43 void NotifyRenderers(); 44 45 private: 46 DISALLOW_COPY_AND_ASSIGN(TimeZoneMonitor); 47}; 48 49} // namespace content 50 51#endif // CONTENT_BROWSER_TIME_ZONE_MONITOR_H_ 52