Implement :properties pseudo-class

[ameshkov]

Synonym for :abp-properties.

Don't implement it right away, please take a look at their implementation first.

As I understand it works as matches-css + matches-css-before + matches-css-after

[theseanl]

Done in #59

[theseanl]

It turned out that the overhead caused by processing the whole document at document start is quite substantial, e.g. on facebook.com. Since this is unavoidable, we should provide some mechanism for dividing styles processing into several chunks.

[ameshkov]

It appears that the performance problems are not due to the stylesheets scanning. Please investigate and fix it.

This data was recorded with https://gist.github.com/ameshkov/2d06530839ceefbe2027d95486ece1a3

ExtendedCss.query('div[id^="hyperfeed_story_id_"]:-abp-has(a[href="#"]:-abp-properties(content: "Sponsored"))')
VM10733:3243 StyleObserver initial processing: 1.155029296875ms
VM10733:4097 [ExtendedCss] Elapsed: 290830 μs.
4VM10733:99 {
    "AsyncWrapper.prototype.runImmediately": {
        "name": "AsyncWrapper.prototype.runImmediately",
        "count": 16190,
        "totalElapsed": 13.065000000011423,
        "averageElapsed": 0.0008069796170482658,
        "minElapsed": 0,
        "maxElapsed": 0.13999999999941792,
        "errors": 0
    },
    "AsyncWrapper.prototype.runAsap": {
        "name": "AsyncWrapper.prototype.runAsap",
        "count": 8095,
        "totalElapsed": 142.24500000002354,
        "averageElapsed": 0.017571957998767578,
        "minElapsed": 0.009999999999308784,
        "maxElapsed": 0.2900000000008731,
        "errors": 0
    },
    "StyleObserver.getSelector": {
        "name": "StyleObserver.getSelector",
        "count": 8095,
        "totalElapsed": 242.5949999999757,
        "averageElapsed": 0.02996849907349916,
        "minElapsed": 0.019999999998617568,
        "maxElapsed": 1.3800000000001091,
        "errors": 0
    },
    "Sizzle.selectors.pseudos.properties": {
        "name": "Sizzle.selectors.pseudos.properties",
        "count": 8095,
        "totalElapsed": 259.0500000000038,
        "averageElapsed": 0.03200123533045137,
        "minElapsed": 0.020000000000436557,
        "maxElapsed": 4.139999999999418,
        "errors": 0
    }
}

[theseanl]

For documentations sake, reposting a comment #55 (comment).

All the performance concerns were caused by compilerCache being missed. Simply calling Sizzle.compile on certain selectors restores the performance of the previous version. This is looks like a bug of Sizzle, and it seems to be fixed in Sizzle's master branch.