Re: Call for Consensus: Incubations adoption

> Mozilla is interested in prototyping layout instability, but is concerned
> about the potential overhead in making this a part of a standard and
> required for every page load.

Google also encountered challenges making layout instability performant.
In the spec and explainer for layout instability, we tried to emphasize the
possibility of trading off precision for computational efficiency.  For
example, Chrome's initial implementation snapped visual representations to
a low-resolution grid to calculate the impact region.

We also added a note in spec section 2.3 with links to resources about the
Klee measure problem and the O(n lg n) algorithm we ended up with in
LayoutShiftRegion
<https://source.chromium.org/chromium/chromium/src/+/master:third_party/blink/renderer/core/layout/layout_shift_region.h>
..

There has also been some recent discussion about simplifying bounding rects
for inlines, in https://crbug.com/1108622#c2.  However, the spec has not
yet been updated to reflect that proposal.

In my opinion, for a feature like layout instability, user agents ought to
have some flexibility to make implementation decisions that best fit their
rendering architecture, even at the cost of minor cross-browser divergences
in reported scores.  See
https://github.com/WICG/layout-instability/blob/master/README.md#precision-variance-and-evolution
..