Removed "width" feature from the popup condition, and removed related parameters
(aWidthSpecified, and aSizeSpec) from functions.
Also added "popup" feature that explicitly specify whether to request popup or
not.
This is only for content context, and it behaves differently than existing
"popup" feature for chrome context that makes the window no-style.
Differential Revision: https://phabricator.services.mozilla.com/D129410
