Backed out changeset d7f58753a981 (bug 1518946) per developer's request on IRC

browser/base/content/test/webrtc/browser.ini

@@ -24,4 +24,3 @@ skip-if = (os == "win" && bits == 64) # win8: bug 1334752
 [browser_devices_get_user_media_unprompted_access_queue_request.js]
 [browser_webrtc_hooks.js]
 [browser_devices_get_user_media_queue_request.js]
-skip-if = (os == 'mac') || (os =='linux') # Bug 1518946