Comment on attachment 9043133 [details]
Bug 1527120: Disable "dynamic reflow root" feature on beta, due to having at least one unresolved regression. r?dbaron
Beta/Release Uplift Approval Request
Feature/Bug causing the regression
User impact if declined
Broken layout, in pages where the optimization takes effect & where bug 1510360 rears its head
Is this code covered by automated tests?
Has the fix been verified in Nightly?
Needs manual test from QE?
If yes, steps to reproduce
List of other uplifts needed
Risk to taking this patch
Why is the change risky/not risky? (and alternatives if risky)
This change is just preffing off a recently-added opportunistic optimization (one which is probably activated infrequently, in the real world), because it's known to break layout in some cases. The optimization was only added in the Firefox 66 timeframe (bug 1159042) so that's where I'd like to pref it off.
(I'm leaving it on in Nightly because the known regression isn't too bad and I'm hoping to fix it soon; but for Beta we might as well just pref it off.)
String changes made/needed