1735511 - remove IsScrollingActive check in nsDisplayListBuilder::IsAnimatedGeometryRoot

Status: RESOLVED FIXED

(Core :: Web Painting, enhancement)

Comment 1

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1735511. Remove IsScrollingActive check in nsDisplayListBuilder::IsAnimatedGeometryRoot. r?mattwoodrow,miko,botond

This only changes the return value in the case that IsScrollingActive is false but IsMaybeAsynchronouslyScrolled is true. This is an impossible case. If IsScrollingActive is false then the scrollframe can't be IsAlwaysActive, which is only true for root content documents. Also if IsScrollingActive is false then HasScrollGrab and HasDisplayPort are both false.

If IsMaybeAsynchronouslyScrolled is true then either HasDisplayPort, HasScrollGrab, or mZoomableByAPZ must be true. The first two are already ruled out. mZoomableByAPZ is only true on root content documents, so that too is ruled out.

In general we want to move away from IsScrollingActive for async scrolling things. There are only a few callers left, probably only one of them actually wants the concept that IsScrollingActive uses. Once we've removed the other users we can rename it to something like "HasBeenScrolledRecently" or something like that to avoid confusing with active scrolled roots and the use of the word active to mean async scrolling type things.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ffa60d8faa5b
Remove IsScrollingActive check in nsDisplayListBuilder::IsAnimatedGeometryRoot. r=mattwoodrow

Comment 3

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/ffa60d8faa5b