chromeos: Add power supply info reading capability

chrome/browser/chromeos/net/network_change_notifier_chromeos.cc

Index: chrome/browser/chromeos/net/network_change_notifier_chromeos.cc
diff --git a/chrome/browser/chromeos/net/network_change_notifier_chromeos.cc b/chrome/browser/chromeos/net/network_change_notifier_chromeos.cc
index b2ff7584ec9e0111a1940cbb18fa9de690818c11..b45eb768b0d2024c47740933f50c945d3c7b574d 100644
--- a/chrome/browser/chromeos/net/network_change_notifier_chromeos.cc
+++ b/chrome/browser/chromeos/net/network_change_notifier_chromeos.cc
@@ -6,6 +6,7 @@
 
 #include "base/bind.h"
 #include "chrome/browser/chromeos/cros/cros_library.h"
+#include "chrome/browser/chromeos/dbus/dbus_thread_manager.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace {
@@ -67,9 +68,13 @@ NetworkChangeNotifierChromeos::NetworkChangeNotifierChromeos()
       chromeos::CrosLibrary::Get()->GetNetworkLibrary();
   net->AddNetworkManagerObserver(this);
 
-  chromeos::PowerLibrary* power =
+  chromeos::PowerLibrary* power_lib =
       chromeos::CrosLibrary::Get()->GetPowerLibrary();
-  power->AddObserver(this);
+  power_lib->AddObserver(this);
+
+  chromeos::PowerManagerClient* power_client =
+      chromeos::DBusThreadManager::Get()->power_manager_client();
+  power_client->AddObserver(this);
 
   UpdateNetworkState(net);
   BrowserThread::PostDelayedTask(
@@ -91,9 +96,13 @@ NetworkChangeNotifierChromeos::~NetworkChangeNotifierChromeos() {
   lib->RemoveNetworkManagerObserver(this);
   lib->RemoveObserverForAllNetworks(this);
 
-  chromeos::PowerLibrary* power =
+  chromeos::PowerLibrary* power_lib =
       chromeos::CrosLibrary::Get()->GetPowerLibrary();
-  power->RemoveObserver(this);
+  power_lib->RemoveObserver(this);
+
+  chromeos::PowerManagerClient* power_client =
+      chromeos::DBusThreadManager::Get()->power_manager_client();
+  power_client->RemoveObserver(this);
 }
 
 void NetworkChangeNotifierChromeos::PowerChanged(