The shownFiles array was referenced in _setReviewedFiles instead of the
files array, causing an undefined error due to accessing an array with
an out of bounds index.
This change fixes that, and removes the stub call that would have caught
this issue.
Bug: Issue 5853
Change-Id: I17175796d8d67ca4d53f6ce2f82a59ff2ebc4010
(cherry picked from commit 7011651093)