Battery Status API: blink promise implementation and layout tests.

Source/modules/battery/NavigatorBattery.h

 // Copyright 2014 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.
 
 #ifndef NavigatorBattery_h
 #define NavigatorBattery_h
 
+#include "bindings/v8/ScriptPromise.h"
 #include "core/frame/Navigator.h"
 #include "platform/Supplementable.h"
 #include "platform/heap/Handle.h"
 
 namespace WebCore {
 
 class BatteryManager;
 class Navigator;
 
 class NavigatorBattery FINAL : public NoBaseWillBeGarbageCollectedFinalized<NavigatorBattery>, public WillBeHeapSupplement<Navigator> {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(NavigatorBattery);
 public:
     virtual ~NavigatorBattery();
 
     static NavigatorBattery& from(Navigator&);
 
-    static BatteryManager* battery(Navigator&);
-    BatteryManager* batteryManager(Navigator&);
+    static ScriptPromise getBattery(ScriptState*, Navigator&);
+    ScriptPromise getBattery(ScriptState*);
 
     void trace(Visitor*);
 
 private:
     NavigatorBattery();
     static const char* supplementName();
 
     RefPtrWillBeMember<BatteryManager> m_batteryManager;
 };
 
 } // namespace WebCore
 
 #endif // NavigatorBattery_h