Disable battery power detection on POSIX since we don't currently use it.

base/system_monitor.cc

 // Copyright (c) 2008 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.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 
 namespace base {
 
+#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()
     : battery_in_use_(false),
       suspended_(false) {
   observer_list_ = new ObserverListThreadSafe<PowerObserver>();
 }
 
 void SystemMonitor::ProcessPowerMessage(PowerEvent event_id) {
-  // Suppress duplicate notifications.  Some platforms may 
+  // 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();
         }
       }
@@ skipping 15 matching lines @@
 
 void SystemMonitor::AddObserver(PowerObserver* obs) {
   observer_list_->AddObserver(obs);
 }
 
 void SystemMonitor::RemoveObserver(PowerObserver* obs) {
   observer_list_->RemoveObserver(obs);
 }
 
 void SystemMonitor::NotifyPowerStateChange() {
-  LOG(INFO) << L"PowerStateChange: " 
+  LOG(INFO) << L"PowerStateChange: "
            << (BatteryPower() ? L"On" : L"Off") << L" battery";
   observer_list_->Notify(&PowerObserver::OnPowerStateChange, this);
 }
 
 void SystemMonitor::NotifySuspend() {
   LOG(INFO) << L"Power Suspending";
   observer_list_->Notify(&PowerObserver::OnSuspend, this);
 }
 
 void SystemMonitor::NotifyResume() {
   LOG(INFO) << L"Power Resuming";
   observer_list_->Notify(&PowerObserver::OnResume, this);
 }
 
 void SystemMonitor::Start() {
+#if defined(ENABLE_BATTERY_MONITORING)
   DCHECK(MessageLoop::current());  // Can't call start too early.
   SystemMonitor* monitor = Get();
   monitor->delayed_battery_check_.Start(
       TimeDelta::FromMilliseconds(kDelayedBatteryCheckMs), monitor,
       &SystemMonitor::BatteryCheck);
+#endif  // defined(ENABLE_BATTERY_MONITORING)
 }
 
 void SystemMonitor::BatteryCheck() {
   ProcessPowerMessage(SystemMonitor::POWER_STATE_EVENT);
 }
 
 } // namespace base