Fix global exceptions in karma.conf.js for chartnewjs

Three globals were missing and causing tests to fail.

TBR=ojan@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/542953003

git-svn-id: svn://svn.chromium.org/blink/trunk@181586 bbb929c8-8fbe-4397-9dbb-9b2b20218538