base/timer/hi_res_timer_manager_win.cc

   1 // Copyright (c) 2011 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 #include "base/timer/hi_res_timer_manager.h"
   6
   7 #include "base/power_monitor/power_monitor.h"
   8 #include "base/time/time.h"
   9
  10 namespace base {
  11
  12 HighResolutionTimerManager::HighResolutionTimerManager()
  13     : hi_res_clock_available_(false) {
  14   base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
  15   DCHECK(power_monitor != NULL);
  16   power_monitor->AddObserver(this);
  17   UseHiResClock(!power_monitor->IsOnBatteryPower());
  18 }
  19
  20 HighResolutionTimerManager::~HighResolutionTimerManager() {
  21   base::PowerMonitor::Get()->RemoveObserver(this);
  22   UseHiResClock(false);
  23 }
  24
  25 void HighResolutionTimerManager::OnPowerStateChange(bool on_battery_power) {
  26   UseHiResClock(!on_battery_power);
  27 }
  28
  29 void HighResolutionTimerManager::UseHiResClock(bool use) {
  30   if (use == hi_res_clock_available_)
  31     return;
  32   hi_res_clock_available_ = use;
  33   base::Time::EnableHighResolutionTimer(use);
  34 }
  35
  36 }  // namespace base