1585589 - privacy.resistFingerprinting makes tab strip scrolling with overflow arrows unsmooth

Status: VERIFIED FIXED

(Core :: DOM: Animation, defect)

Description

[Kestrel]

STR:

1. Set privacy.resistFingerprinting = true.
2. Create enough new tabs to overflow the tab strip.
3. Click and hold the overflow arrows to scroll the tab strip continuously.

Expected:

Tab strip scrolls smoothly.

Actual:

Tab strip jumps and stutters with RFP enabled, making it harder to visually track the movement.

Mousewheel scrolling in the tab strip is unaffected.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=aff36ef651a7705800156e86076197d8a202afa7&tochange=02bfa4baa2edd2d1c9417018c4cbd85e99d15aa8

Regressed by Bug 1577243.

Comment 1

[Brian Birtles (:birtles)]

That bug shouldn't affect the performance of declarative animation but I guess this animation is a JS animation. Perhaps this here:

https://searchfox.org/mozilla-central/rev/35cc00a25c4471993fdaa5761952bd3afd4f1731/toolkit/content/widgets/scrollbox.xml#101-122

Dão is that right?

Comment 2

[Brian Birtles (:birtles)]

Tom, any ideas how this should work? Are there other reports of JS animations becoming janky with RFP after that bug?

Comment 3

[Tom Ritter [:tjr]]

No other reports. In most callsites we check the system principal and don't reduce in that case. I don't have such a condition in rAF - I'll have to see how to add it there.

Comment 4

[Tom Ritter [:tjr]]

Attachment: Bug 1585589 - Do not reduce the precision of the requestAnimationFrame timestamp if we are in the System Principal Context r?birtles

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c38b3c03d21f
Do not reduce the precision of the requestAnimationFrame timestamp if we are in the System Principal Context r=birtles

Comment 6

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/c38b3c03d21f

Comment 7

[Cristian Fogel [:cfogel]]

Confirmed issue with 71.0a1(20191002214349) on Windows 10.
Fix verified with 71.0b8 on Windows 10, macOS 10.13.6, Ubuntu 18.04.