Cleanup: Add more conversion helpers for usage.

Source/modules/device_orientation/DeviceOrientationEvent.h

 /*
  * Copyright 2010, The Android Open Source Project
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 44 matching lines @@
 
     virtual const AtomicString& interfaceName() const;
 
 private:
     DeviceOrientationEvent();
     DeviceOrientationEvent(const AtomicString& eventType, DeviceOrientationData*);
 
     RefPtr<DeviceOrientationData> m_orientation;
 };
 
+inline DeviceOrientationEvent* toDeviceOrientationEvent(Event* event)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(!event || event->interfaceName() == EventNames::deviceorientation);

[tkent, 2013/10/10 01:51:13]

EventNames::deviceorientation should be
eventNames().interfaceForDeviceOrientationEvent.

+    return static_cast<DeviceOrientationEvent*>(event);
+}
+
 } // namespace WebCore
 
 #endif // DeviceOrientationEvent_h