Bug 1533282 - Restore the debugging options in wrench/script/headless.py. r=kvark,kats
Bug 1533282 - Restore the debugging options in wrench/script/headless.py. r=kvark,kats

Differential Revision: https://phabricator.services.mozilla.com/D22458

[wrupdater] From https://hg.mozilla.org/mozilla-central/rev/c8f81797dbaebbddf9fc807febad5c11942b8cf8

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender