core(full-page-screenshot): use dpr 1

[paulirish]

followup from #11118 and #11536

I originally hesitated about changing DPR but patrick convinced me here (and in some followup conversations) it's better to change DPR to 1 for our FPS.

Taller image. more coverage. The risk is lower than the risk we already encounter by changing the height (viz observers, etc).

To test this.

node lighthouse-cli https://paulirish.github.io/tiny-demos-on-https/pixel-ruler.html?maxPxHeight=20000 --only-audits=full-page-screenshot --preset=experimental

then in the report:

const img = new Image(); img.src = __LIGHTHOUSE_JSON__.audits["full-page-screenshot"].details.data;  document.body.prepend(img);

[connorjclark]

removing all of this is necessary? IIRC you suggested I add all the parameters in the original PR.

[paulirish]

yeah i was being overly cautious back then. i looked and neither CDT nor PPTR uses these props.
i tested this heavily after these changes and feel good that they aren't important.

[connorjclark]

Did you check if the cases that were fixed recently are still good with this change?

#11538
#11402
#11536

[connorjclark]

iffy on fpss (does the full thing fit)? but it should certainly be fps :)

[paulirish]

good question

Did you check if the cases that were fixed recently are still good with this change?

#11538

ya

paulirish.github.io/tiny-demos-on-https/pixel-ruler.html?maxPxHeight=20000&color=ccc

#11402

ya

#11536

yeaup

https://googlechrome.github.io/lighthouse/viewer/?gist=b01f0140619ad5aca1953f532bf85149

[connorjclark]

Thanks for checking.

googlechrome.github.io/lighthouse/viewer/?gist=b01f0140619ad5aca1953f532bf85149

I don't see any images.

[paulirish]

Thanks for checking.

googlechrome.github.io/lighthouse/viewer/?gist=b01f0140619ad5aca1953f532bf85149

I don't see any images.

TRUE!

it was fine locally but it put it up on viewer.. and.. looks like some problems.

... investigating...

---

update:

oh its just the changes to the FPS audit payload. you changed it in the resolve-nodes branch.. and to verify this PR works.. i merged the two locally.. but the hosted viewer doesn't have the changes.

anyway we all good.

[Beytoven]

LGTM. Gonna lean on @connorjclark to give the final approval though.

[connorjclark]

i don't understand this change to the default

[paulirish]

good call. it's kind of a separate change. This is the mock driver so we're returning a DPR back to lighthouse.

Since we're now emulating DPR 1 to take the screenshot.. I figured I'd just pretend the browser is a non-1 DPR just to keep things separate

afaik this value is never even used.......

......

okay in that case i'll just delete this part of the mock.
done.

[connorjclark]

oops I happened to already do a commit like core(full-page-screenshot): ... (7845154) soooo for consistencies sake....