Request power status update from power manager when power button view gets created.

Also, prepare PowerManagerDbusClient for change in power manager for bug chromium-os:21360

TEST=manual
BUG=chromium-os:20832


Review URL: http://codereview.chromium.org/8491054

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109777 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/status/power_menu_button.cc

@@ -217,6 +217,7 @@ PowerMenuButton::PowerMenuButton(StatusAreaButton::Delegate* delegate)
   set_id(VIEW_ID_STATUS_BUTTON_POWER);
   UpdateIconAndLabelInfo();
   DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(this);
+  DBusThreadManager::Get()->GetPowerManagerClient()->RequestStatusUpdate();
 }
 
 PowerMenuButton::~PowerMenuButton() {