GitLab

This methods accept callback which will be called when scripts finished execution.

R=vsevik@chromium.org
BUG=410289

Review URL: https://codereview.chromium.org/660863002

git-svn-id: svn://svn.chromium.org/blink/trunk@184279 bbb929c8-8fbe-4397-9dbb-9b2b20218538