1718384 - Don't use viewport units in #fullscreen-and-pointerlock-wrapper

Status: RESOLVED FIXED

(Firefox :: General, task)

Description

[Emilio Cobos Álvarez (:emilio)]

+++ This bug was initially created as a clone of Bug #1718337 +++

This is the only usage of viewport units in the whole browser window and we could live without it trivially. It avoids otherwise-unnecessary style invalidation.

In the cloned bug I've improved the style system so that we do a lot less work, but we still need to do a full DOM walk.

Instead let's use percentages, which only need re-layout, not restyle (viewport units compute to a pixel value, percentages compute to themselves).

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1718384 - Don't unnecessarily use viewport units in #fullscreen-and-pointerlock-wrapper. r=Gijs,dao

This is the only usage of viewport units in the whole browser window and
we could live without it trivially. It avoids otherwise-unnecessary
style invalidation.

In the cloned bug I've improved the style system so that we do a lot
less work, but we still need to do a full DOM walk.

Instead let's use percentages, which only need re-layout, not restyle
(viewport units compute to a pixel value, percentages compute to
themselves).

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9a34111fd0f4
Don't unnecessarily use viewport units in #fullscreen-and-pointerlock-wrapper. r=Gijs

Comment 3

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/9a34111fd0f4

Comment 4

[Alexandru Ionescu (needinfo me) [:alexandrui]]

== Change summary for alert #30513 (as of Wed, 07 Jul 2021 05:45:29 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
28%	tresize		windows10-64-shippable-qr	e10s stylo webrender	8.72 -> 6.25
28%	tresize		macosx1014-64-shippable-qr	e10s stylo webrender	8.95 -> 6.43
28%	tresize		macosx1014-64-shippable-qr	e10s stylo webrender-sw	9.24 -> 6.66
27%	tresize		macosx1015-64-shippable-qr	e10s stylo webrender	6.84 -> 5.01
27%	tresize		macosx1015-64-shippable-qr	e10s stylo webrender-sw	7.10 -> 5.21
...	...	...	...	...	...
16%	tresize		linux1804-64-shippable-qr	e10s stylo webrender	21.53 -> 18.07

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=30513