Fix the Recenter Selected Chunk (Enter key) feature in the diff viewer.
Review Request #435 - Created Feb. 27, 2017 and discarded
The Recenter code was assuming it was working with a jQuery, when instead it got a DOM element. This change fixes this so that Enter works again. Patch by Laurent Nicolas. Reviewed at http://reviews.reviewboard.org/r/1507/
just ran few manual tests