Gardening: battery-status/page-visibility.html is failing

BUG=419515
TBR=sigbjornf@opera.com,eustas@chromium.org

Review URL: https://codereview.chromium.org/616383003

git-svn-id: svn://svn.chromium.org/blink/trunk@183087 bbb929c8-8fbe-4397-9dbb-9b2b20218538