Element hiding emulation uses inline styles for plain selectors

[mjethani]

Environment

ABP 3.0.3 on Chrome 66

How to reproduce

1. Add the filter example.com#?#p
2. Visit ​https://example.com/
3. Open the DevTools inspector to examine the DOM

Observed behaviour

The <p> elements are hidden by setting the style="..." attribute

Expected behaviour

The <p> elements should be hidden using a CSS selector

Notes

The reason this matters is that plain selectors are not dependent on DOM mutations, so we ​don't process these (#6437) when there's a mutation. If we use CSS selectors in the first place there's no need to process these selectors each time there's a mutation.

[hfiguiere]

No. That's the correct behaviour for a #?# filter. Simple element hiding with style sheets should be a filter of type ##.

[mjethani]

What is the rationale for this? It seems like a no-brainer to use a CSS selector in this case instead of calling querySelectorAll each time there's a mutation.

One more thing to note is that a CSS selector would also apply to shadow DOMs whereas querySelectorAll only works on the light DOM.

[mjethani]

Also by the way since we have switched to user style sheets this is kind of moot, we are already using CSS selectors here if tabs.removeCSS is available.

[hfiguiere]

This was issue #5314

This was before user stylesheets in Chrome.

[mjethani]

OK, this makes sense. Anyway if we make the change for #6610 then it's going to go the other way. I'll close this.