Cleanup: Add more conversion helpers for usage.

Source/modules/device_orientation/DeviceMotionEvent.h

Index: Source/modules/device_orientation/DeviceMotionEvent.h
diff --git a/Source/modules/device_orientation/DeviceMotionEvent.h b/Source/modules/device_orientation/DeviceMotionEvent.h
index bf1824cc5b183e7306bea41fd5d589959345ff37..2204b80dec8f915a6a8ee508d76180bc03505ba2 100644
--- a/Source/modules/device_orientation/DeviceMotionEvent.h
+++ b/Source/modules/device_orientation/DeviceMotionEvent.h
@@ -68,6 +68,12 @@ private:
     RefPtr<DeviceRotationRate> m_rotationRate;
 };
 
+inline DeviceMotionEvent* toDeviceMotionEvent(Event* event)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(event && event->type() == eventNames().devicemotionEvent);

[tkent, 2013/10/08 05:24:04]

This is wrong.
 - should accept NULL event
 - checking Event::type() is incorrect because a script can set arbitrary
strings to the type.  We should use interfaceName().

[r.kasibhatla, 2013/10/08 09:40:15]

Done.

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