make a top level reference to QuizTakingPolice
make a top level reference to QuizTakingPolice

fixes CNVS-28931

TEST PLAN:
 1) build a timed quiz
 2) take quiz in Chrome 50
 3) timer should work

Change-Id: I93d8f591197bd7d1efed5ef13fba0df44abca3f1

grahamb/canvas-lms,grahamb/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,fronteerio/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,SwinburneOnline/canvas-lms,SwinburneOnline/canvas-lms,roxolan/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,fronteerio/canvas-lms,roxolan/canvas-lms,grahamb/canvas-lms,venturehive/canvas-lms,roxolan/canvas-lms,HotChalk/canvas-lms,fronteerio/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,roxolan/canvas-lms,fronteerio/canvas-lms