Fix private style in ct-commit-data.html.

Also, while at it, add a basic test to make sure this code executes
correctly.

NOTRY=true

Review URL: https://codereview.chromium.org/380983002

git-svn-id: svn://svn.chromium.org/blink/trunk@177804 bbb929c8-8fbe-4397-9dbb-9b2b20218538