The early meaning “to look at obliquely” has become a direct stare.  Even more interesting, OED suggests that goggle is an onomatopoeic word, expressive of oscillating movement.  Ahem.  Now we know what sound Gollum’s eyeballs make?

• 08.114 and hundreds of angry spiders were goggling at them all round

“goggle, v.1.” OED Online. Oxford University Press, March 2015. Web. 1 June 2015.