1578777 - Div is not scrollable with mouse(but possible with dragging the scrollbar) when WebRender is enabled

Status: VERIFIED FIXED

(Core :: Graphics: WebRender, defect, P3)

Description

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

I encountered this while I was looking on a profile in profiler.firefox.com.
STR:

1. Open https://perfht.ml/34mruX1 .
2. Make the window height narrower so we can see the scrollbar.
3. Click to the "Firefox (65.0) Intel Mac OS X 10.14" text on top right corner to open the metadata popup panel.
4. Try to scroll with your mouse without dragging the scrollbar

It works without webrender enabled and realized that it works with previous versions of webrender. Did a mozregression run and found out that this is regressed by https://hg.mozilla.org/integration/autoland/rev/c0a07a2c5d0263b35ceb271c668a41256b959630 (Bug 1550510).

Comment 1

[Jessie [:jbonisteel] pls NI]

I could reproduce this on my mac. Jeff, any suggestions?

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Let's ask Botond

Comment 3

[Botond Ballo [:botond]]

The scrollable element in question is not being layerized for some reason, even after user interaction.

Comment 4

[Botond Ballo [:botond]]

It's not being layerized because it's inside a filter that WebRender doesn't support.

Bug 1550510 assumed that with WR we can handle all filters in the compositor and therefore we can layerize all scrollable elements inside filters. That's not the case.

Comment 5

[Botond Ballo [:botond]]

Attachment: Bug 1578777 - Remove non-ASCII character from comment in WebRenderCommandBuilder.cpp. r=jrmuizel

Comment 6

[Botond Ballo [:botond]]

Attachment: Bug 1578777 - Remove the builder parameter from nsDisplayFilters::CreateWebRenderCommands(). r=jrmuizel

It was unused.

Depends on D46057

Comment 7

[Botond Ballo [:botond]]

Attachment: Bug 1578777 - Move CreateWebRenderCSSFilters() to nsSVGIntegrationUtils. r=jrmuizel

Depends on D46058

Comment 8

[Botond Ballo [:botond]]

Attachment: Bug 1578777 - Introduce a helper nsSVGIntegrationUtils::CanCreateWebRenderFiltersForFrame(). r=jrmuizel

Depends on D46059

Comment 9

[Botond Ballo [:botond]]

Attachment: Bug 1578777 - Use CanCreateWebRenderFiltersForFrame() in ScrollFrameWillBuildScrollInfoLayer(). r=tnikkel

Depends on D46060

Comment 10

[Botond Ballo [:botond]]

Attachment: Bug 1578777 - Move UsesSVGEffectsNotSupportedInCompositor() to nsSVGIntegrationUtils. r=tnikkel

Depends on D46061

Comment 11

[Botond Ballo [:botond]]

Attachment: Bug 1578777 - Use UsesSVGEffectsNotSupportedInCompositor() in ShouldBuildScrollInfoItemsForHoisting(). r=tnikkel

This required replacing nsDisplayListBuilder::mSVGEffectsBuildingDepth with
a stack of the SVG effects frames that we're currently building inside.

Depends on D46063

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ff6a071cf39e
Remove non-ASCII character from comment in WebRenderCommandBuilder.cpp. r=jrmuizel
https://hg.mozilla.org/integration/autoland/rev/773809005683
Remove the builder parameter from nsDisplayFilters::CreateWebRenderCommands(). r=jrmuizel
https://hg.mozilla.org/integration/autoland/rev/29130e26511b
Move CreateWebRenderCSSFilters() to nsSVGIntegrationUtils. r=jrmuizel
https://hg.mozilla.org/integration/autoland/rev/430834640980
Introduce a helper nsSVGIntegrationUtils::CanCreateWebRenderFiltersForFrame(). r=jrmuizel
https://hg.mozilla.org/integration/autoland/rev/c278c4ce9447
Use CanCreateWebRenderFiltersForFrame() in ScrollFrameWillBuildScrollInfoLayer(). r=tnikkel
https://hg.mozilla.org/integration/autoland/rev/b3d7b5f40cf7
Move UsesSVGEffectsNotSupportedInCompositor() to nsSVGIntegrationUtils. r=tnikkel
https://hg.mozilla.org/integration/autoland/rev/504f24d73316
Use UsesSVGEffectsNotSupportedInCompositor() in ShouldBuildScrollInfoItemsForHoisting(). r=tnikkel

Comment 13

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/ff6a071cf39e
https://hg.mozilla.org/mozilla-central/rev/773809005683
https://hg.mozilla.org/mozilla-central/rev/29130e26511b
https://hg.mozilla.org/mozilla-central/rev/430834640980
https://hg.mozilla.org/mozilla-central/rev/c278c4ce9447
https://hg.mozilla.org/mozilla-central/rev/b3d7b5f40cf7
https://hg.mozilla.org/mozilla-central/rev/504f24d73316

Comment 14

[Cristian Fogel [:cfogel]]

Tentative addition of QE+, will be removed if our hardware configuration(s) does allow us to reproduce the issue.

Comment 15

[Alexandru Trif, Desktop QA [:atrif]]

Hello! Reproduced the issue with Firefox 71.0a1 (20190904163258) on Windows 10x64.
The issue is verified fixed with Firefox 71.0b9 (20191111170815) on Windows 10x64, Ubuntu 18.04 and macOS 10.14. After following the STR from comment 0 the dropdown menu is scrollable while using Webrender.