Inject element hiding CSS wih chrome.tabs.insertCSS()

[sebastian]

Background

Starting with Chrome 41 chrome.tabs.insertCSS() will ​allow to inject CSS per frame. This approach is preferable over injecting a <style> element with a content script, because it leads to less side effects, and should be more efficient than using Shadow DOM.

What to change

Once Chrome allows to limit chrome.tabs.insertCSS() per frame, use it to implement element hiding on supported Chrome versions. Keep the former approach, injecting a <style> element, as fallback for older Chrome and Opera versions, as well as for Safari.

[trev]

Won't this make issues similar to #242 even more prevalent? My understanding is that any rule defined by the web page will always override the ones we define.

[sebastian]

Unfortunately you are right. I just tested it, and any <style> and <link rel="stylesheet"> element provided by the web page overrides stylesheets injected with chrome.tabs.insertCSS(), when the conflicting rules have the same priority. However, Shadow DOM lets us override all stylesheets of the web page, except those configured with style attributes, using !important priority.

[trev]

Splitting hairs here but the correct resolution would be "rejected" I think.

[sebastian]

I'd say it's invalid, because the issue was filed under wrong assumptions.