DevTools: Enable Rhino-based frontend JSDoc validator

R=vsevik, yurys
BUG=328064
NOTRY=true

Review URL: https://codereview.chromium.org/110913006

git-svn-id: svn://svn.chromium.org/blink/trunk@163868 bbb929c8-8fbe-4397-9dbb-9b2b20218538