Adding image for LinkHighlighting test.
Tests in https://codereview.chromium.org/24110002/
Original author: bokan@chromium.org

TBR=bokan@chromium.org

BUG=170673

Review URL: https://codereview.chromium.org/23609055

git-svn-id: svn://svn.chromium.org/blink/trunk@157912 bbb929c8-8fbe-4397-9dbb-9b2b20218538