SystemMonitor refactoring: move power state monitor into a separate class called PowerMonitor

base/power_monitor/power_monitor.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright 2013 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 "base/system_monitor/system_monitor.h"
+#include "base/power_monitor/power_monitor.h"
 
-#include <utility>
-
-#include "base/logging.h"
-#include "base/message_loop.h"
 #include "base/time.h"
 
 namespace base {
 
-static SystemMonitor* g_system_monitor = NULL;
+static PowerMonitor* g_power_monitor = NULL;
 
 #if defined(ENABLE_BATTERY_MONITORING)
 // The amount of time (in ms) to wait before running the initial
 // battery check.
 static int kDelayedBatteryCheckMs = 10 * 1000;
 #endif  // defined(ENABLE_BATTERY_MONITORING)
 
-SystemMonitor::SystemMonitor()
-    : power_observer_list_(new ObserverListThreadSafe<PowerObserver>()),
-      devices_changed_observer_list_(
-          new ObserverListThreadSafe<DevicesChangedObserver>()),
+PowerMonitor::PowerMonitor()
+    : observers_(new ObserverListThreadSafe<PowerObserver>()),
       battery_in_use_(false),
       suspended_(false) {
-  DCHECK(!g_system_monitor);
-  g_system_monitor = this;
+  DCHECK(!g_power_monitor);
+  g_power_monitor = this;
 
   DCHECK(MessageLoop::current());
 #if defined(ENABLE_BATTERY_MONITORING)
   delayed_battery_check_.Start(FROM_HERE,
       base::TimeDelta::FromMilliseconds(kDelayedBatteryCheckMs), this,
-      &SystemMonitor::BatteryCheck);
+      &PowerMonitor::BatteryCheck);
 #endif  // defined(ENABLE_BATTERY_MONITORING)
 #if defined(OS_MACOSX)
   PlatformInit();
 #endif
 }
 
-SystemMonitor::~SystemMonitor() {
+PowerMonitor::~PowerMonitor() {
 #if defined(OS_MACOSX)
   PlatformDestroy();
 #endif
-  DCHECK_EQ(this, g_system_monitor);
-  g_system_monitor = NULL;
+  DCHECK_EQ(this, g_power_monitor);
+  g_power_monitor = NULL;
 }
 
 // static
-SystemMonitor* SystemMonitor::Get() {
-  return g_system_monitor;
+PowerMonitor* PowerMonitor::Get() {
+  return g_power_monitor;
 }
 
-void SystemMonitor::ProcessPowerMessage(PowerEvent event_id) {
+void PowerMonitor::AddObserver(PowerObserver* obs) {
+  observers_->AddObserver(obs);
+}
+
+void PowerMonitor::RemoveObserver(PowerObserver* obs) {
+  observers_->RemoveObserver(obs);
+}
+
+void PowerMonitor::ProcessPowerEvent(PowerEvent event_id) {
   // Suppress duplicate notifications.  Some platforms may
   // send multiple notifications of the same event.
   switch (event_id) {
     case POWER_STATE_EVENT:
       {
         bool on_battery = IsBatteryPower();
         if (on_battery != battery_in_use_) {
           battery_in_use_ = on_battery;
           NotifyPowerStateChange();
         }
       }
       break;
     case RESUME_EVENT:
       if (suspended_) {
         suspended_ = false;
         NotifyResume();
       }
       break;
     case SUSPEND_EVENT:
       if (!suspended_) {
         suspended_ = true;
         NotifySuspend();
       }
       break;
   }
 }
 
-void SystemMonitor::ProcessDevicesChanged(DeviceType device_type) {
-  NotifyDevicesChanged(device_type);
+void PowerMonitor::BatteryCheck() {
+  ProcessPowerEvent(PowerMonitor::POWER_STATE_EVENT);
 }
 
-void SystemMonitor::AddPowerObserver(PowerObserver* obs) {
-  power_observer_list_->AddObserver(obs);
+void PowerMonitor::NotifyPowerStateChange() {
+  DVLOG(1) << "PowerStateChange: " << (BatteryPower() ? "On" : "Off")
+           << " battery";
+  observers_->Notify(&PowerObserver::OnPowerStateChange, BatteryPower());
 }
 
-void SystemMonitor::RemovePowerObserver(PowerObserver* obs) {
-  power_observer_list_->RemoveObserver(obs);
+void PowerMonitor::NotifySuspend() {
+  DVLOG(1) << "Power Suspending";
+  observers_->Notify(&PowerObserver::OnSuspend);
 }
 
-void SystemMonitor::AddDevicesChangedObserver(DevicesChangedObserver* obs) {
-  devices_changed_observer_list_->AddObserver(obs);
-}
-
-void SystemMonitor::RemoveDevicesChangedObserver(DevicesChangedObserver* obs) {
-  devices_changed_observer_list_->RemoveObserver(obs);
-}
-
-void SystemMonitor::NotifyDevicesChanged(DeviceType device_type) {
-  DVLOG(1) << "DevicesChanged with device type " << device_type;
-  devices_changed_observer_list_->Notify(
-      &DevicesChangedObserver::OnDevicesChanged, device_type);
-}
-
-void SystemMonitor::NotifyPowerStateChange() {
-  DVLOG(1) << "PowerStateChange: " << (BatteryPower() ? "On" : "Off")
-           << " battery";
-  power_observer_list_->Notify(&PowerObserver::OnPowerStateChange,
-                               BatteryPower());
-}
-
-void SystemMonitor::NotifySuspend() {
-  DVLOG(1) << "Power Suspending";
-  power_observer_list_->Notify(&PowerObserver::OnSuspend);
-}
-
-void SystemMonitor::NotifyResume() {
+void PowerMonitor::NotifyResume() {
   DVLOG(1) << "Power Resuming";
-  power_observer_list_->Notify(&PowerObserver::OnResume);
-}
-
-void SystemMonitor::BatteryCheck() {
-  ProcessPowerMessage(SystemMonitor::POWER_STATE_EVENT);
+  observers_->Notify(&PowerObserver::OnResume);
 }
 
 }  // namespace base