1465133 - Simplify parsing for contain:strict and contain:content

Status: NEW

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Morgan Reschenberg [:morgan]]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36

Steps to reproduce:

Currently, the parsing implementations for contain:strict and contain:content have two bit flags each to preserve whether or not the property was specified verbosely or with the keyword (e.g. contain:strict vs contain:size layout paint style). 



Expected results:

Chrome preserves this property in the specified value, but not in the computed value, and we might want to match that behaviour per the shortest serialisation principle. Instead of having both bit flags (e.g CONTAIN_STRICT and CONTAIN_ALL_BITS), we can simplify the serialisation code to check for just the ALL_BITS and CONTENT_BITS flags instead of both, like the current implementation does, and remove the other flags.