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 11 namespace 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 30 class 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