Battery API won't return updated battery status until client calls didChangeBatteryStatus
https://bugs.webkit.org/show_bug.cgi?id=114891

Patch by Otto Derek Cheung <otcheung@rim.com> on 2013-04-24
Reviewed by Rob Buis.

The BatteryStatus object in BatteryManager won't get updated until BatteryClient calls
didChangeBatteryStatus in BatteryController. Any attempts to call webkitBattery.charged()
or other get functions will always return the default values until the next battery status
change object gets passed to the controller.

We need to update the manager when we attach it to the controller, and update all
existing managers when the controller receives it's first battery status object.

* Modules/battery/BatteryController.cpp:
(WebCore::BatteryController::addListener):
(WebCore::BatteryController::updateBatteryStatus):
* Modules/battery/BatteryManager.cpp:
(WebCore::BatteryManager::didChangeBatteryStatus):
(WebCore::BatteryManager::updateBatteryStatus):
(WebCore):
* Modules/battery/BatteryManager.h:
(BatteryManager):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149063 268f45cc-cd09-0410-ab3c-d52691b4dbfc