Initialize PowerMonitor on_power_battery intitial value for newly created processes.

content/browser/power_monitor_message_broadcaster.cc

 // 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 "content/browser/power_monitor_message_broadcaster.h"
 
 #include "base/power_monitor/power_monitor.h"
 #include "content/common/power_monitor_messages.h"
 #include "ipc/ipc_sender.h"
 
 namespace content {
 
 PowerMonitorMessageBroadcaster::PowerMonitorMessageBroadcaster(
     IPC::Sender* sender)
     : sender_(sender) {
   base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
   if (power_monitor)
     power_monitor->AddObserver(this);
 }
 
 PowerMonitorMessageBroadcaster::~PowerMonitorMessageBroadcaster() {
   base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
   if (power_monitor)
     power_monitor->RemoveObserver(this);
 }
 
+void PowerMonitorMessageBroadcaster::Init() {
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  if (power_monitor)

[cpu_(ooo_6.6-7.5), 2014/07/20 01:33:46]

we don't care if we manage to call IsOnBatteryPower() or not? in what conditions
would it fail?

If it should never fail to obtain a |power_monitor| then we want to CHECK()
here, if we could fail then an explanation of when or why is should be here.

[fmeawad, 2014/07/21 19:54:28]

The CHECK will not be useful here, since there is no code  between the use and
the check, removed the condition.

I looked at where PowerMonitor is initialized, and everywhere the
MessageBroadcaster is currently used, the PowerMonitor is already initialized.

[fmeawad, 2014/07/21 21:48:25]

Actually, I was wrong, unit_tests does not initialize the PowerMonitor, and many
of them run on an IO thread. I restored the condition and added a comment.

+    OnPowerStateChange(power_monitor->IsOnBatteryPower());
+}
+
 void PowerMonitorMessageBroadcaster::OnPowerStateChange(bool on_battery_power) {
   sender_->Send(new PowerMonitorMsg_PowerStateChange(on_battery_power));
 }
 
 void PowerMonitorMessageBroadcaster::OnSuspend() {
   sender_->Send(new PowerMonitorMsg_Suspend());
 }
 
 void PowerMonitorMessageBroadcaster::OnResume() {
   sender_->Send(new PowerMonitorMsg_Resume());
 }
 
 }  // namespace content