With this patch, |NfcConsumer| inherits from |StreamSocket| instead
of |UnixSocketConsumer|. Some methods have been renamed. |NfcConsumer|
now contains the method |GetIO|, which is required by |StreamSocket|
for integration with |ListenSocket|.
This patch changes several small details to make |NfcConsumer| more
correct. This includes
- MOZ_FINAL for classes,
- MOZ_OVERRIDE for virtual methods,
- static global variables, and
- nsAutoPtr around explicitly deleted data.