[DevTools] Run presubmit on protocol changes.

This will catch adding protocol events not implemented in frontend.

BUG=none

Review URL: https://codereview.chromium.org/490083003

git-svn-id: svn://svn.chromium.org/blink/trunk@180733 bbb929c8-8fbe-4397-9dbb-9b2b20218538