Check for NULL before calling asBinder().

The old asBinder() checked if this == NULL, which is undefined behavior.

Change-Id: Ibde628395ca10dfef0d2f59e81280576f104b83c
Merge "Check for NULL before calling asBinder()."
Fix a namespace collision.

There's already an android::FileSource defined in
media/libstagefright/FileSource.h, and the two can conflict at link
time.

Change-Id: Id8d80e96c68af1c9bb2a153630c84b923a4f4d06
Merge "Fix a namespace collision."