Oilpan: move BatteryStatus to the heap.

Source/modules/battery/BatteryManager.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 BatteryManager_h
 #define BatteryManager_h
 
 #include "bindings/v8/ScriptPromise.h"
 #include "bindings/v8/ScriptPromiseResolverWithContext.h"
 #include "core/dom/ContextLifecycleObserver.h"
@@ skipping 35 matching lines @@
     virtual void registerWithDispatcher() OVERRIDE;
     virtual void unregisterWithDispatcher() OVERRIDE;
     virtual bool hasLastData() OVERRIDE;
 
     // ActiveDOMObject implementation.
     virtual bool canSuspend() const { return true; }
     virtual void suspend() OVERRIDE;
     virtual void resume() OVERRIDE;
     virtual void stop() OVERRIDE;
 
+    virtual void trace(Visitor*) OVERRIDE;
+
 private:
     enum State {
         NotStarted,
         Pending,
         Resolved,
     };
 
     explicit BatteryManager(ExecutionContext*);
 
     RefPtr<ScriptPromiseResolverWithContext> m_resolver;
-    RefPtr<BatteryStatus> m_batteryStatus;
+    RefPtrWillBeMember<BatteryStatus> m_batteryStatus;
     State m_state;
 };
 
 }
 
 #endif // BatteryManager_h
-