Use assert() instead of abort() or returning NULL in code that should not be reached.
Use assert() instead of abort() or returning NULL in code that should not be reached.

svn path=/trunk/hubbub/; revision=4406

servo/libhubbub,prepare/netsurf_libhubbub,servo/libhubbub,adamwight/wmf-parsoid-libhubbub,prepare/netsurf_libhubbub,adamwight/wmf-parsoid-libhubbub,Achal-Aggarwal/hibbub,adamwight/wmf-parsoid-libhubbub,Achal-Aggarwal/hibbub,servo/libhubbub,prepare/netsurf_libhubbub,servo/libhubbub,servo/libhubbub,prepare/netsurf_libhubbub,prepare/netsurf_libhubbub,adamwight/wmf-parsoid-libhubbub,Achal-Aggarwal/hibbub,Achal-Aggarwal/hibbub,adamwight/wmf-parsoid-libhubbub,prepare/netsurf_libhubbub