Closed Bug 1501492 Opened Last year Closed Last year

Pref on CSS Containment for use in frontend (separately from content)


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




Tracking Status
firefox65 --- wontfix
firefox66 --- fixed


(Reporter: dholbert, Assigned: dholbert)


(Blocks 1 open bug)



(1 file)

We may want to enable CSS Containment for use in frontend (and devtools in particular) before it's fully ready to ship.

(The motivation would be e.g. to get the "reflow root" optimization from bug 1497414, before parts like "contain:style" have landed. [contain:style is a piece of the standard which we should really land before shipping, but it isn't necessary for the reflow-root optimization that our devtools folks would like to be able to use.])

Filing this bug on doing that.  (IIRC there's some incantation we can use to turn on support for css features in frontend without turning them on for web content in general... I forget the incantation offhand.)
Assignee: nobody → dholbert
I'm marking this as depending on bug 1497414, because there's no big benefit from doing this until that's landed, so we should hold off on this until that's in.

But once that's in, I think we should proceed with this.
Depends on: 1497414
Summary: Pref on CSS Containment for use in devtools (separately from content) → Pref on CSS Containment for use in frontend (separately from content)
(setting needinfo for good measure, since I'm not sure what phabricator's "re-requested review" email looks like)

Note that bug 1497414 landed this morning, so we now should see potential benefits from enabling containment in frontend (via this bug) & setting contain:layout+size on containers around frequently-changing content (in followup bugs).
Flags: needinfo?(dbaron)
As noted in phabricator: at dbaron's suggestion, I wrote a tentative "best practices" doc for frontend developers who are interested in using CSS Containment:
Pushed by
Enable CSS containment for frontend code. r=dbaron
Closed: Last year
Resolution: --- → FIXED
Target Milestone: --- → mozilla66
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