1988030 - Add a way to determine if all scroll frames containing the anchor are active or not at the time of the BuildDisplayList call for the anchored element

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[David Shin[:dshin]]

See Bug 1923392 Comment 15

Comment 1

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1988030. Adjust nsLayoutUtils::GetAsyncScrollableAncestorFrame to be CSS anchor pos aware. r?#layout-reviewers,botond,hiro

We want to assign the ASR of the anchor to the anchored content. That means we are changing the ASR chain so we need to adjust the functions that walk the async scrollable ancestors chain. In this patch we adjust nsLayoutUtils::GetAsyncScrollableAncestorFrame.

Comment 2

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1988030. Adjust DisplayPortUtils::OneStepInAsyncScrollableAncestorChain to be CSS anchor pos aware. r?#layout-reviewers,botond,hiro

We want to assign the ASR of the anchor to the anchored content. That means we are changing the ASR chain so we need to adjust the functions that walk the async scrollable ancestors chain. In this patch we adjust DisplayPortUtils::OneStepInAsyncScrollableAncestorChain.

Comment 3

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1988030. Allow passing a limit ancestor to DisplayPortUtils::OneStepInASRChain that we don't walk past. r?#layout-reviewers,botond,hiro

With CSS anchor pos we know that the anchor is in the containing block of the anchored content. We use that to limit a walk up the frame tree in subsequent patches and make the computation simpler. So we need OneStepInAsyncScrollableAncestorChain to obey that limit too.

Comment 4

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1988030. Create nsLayoutUtils::GetASRAncestorFrame and OneStepInASRChain that walks only scroll frames that are currently async scrollable in the ASR order. r?botond,hiro

I want this so I can assert things in subsequent patches.

WantAsyncScroll and mWillBuildScrollableLayer are completely independent of each other, ie it's possible to have all four combinations of them being true/false.

Comment 5

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1988030. Create a function that activates and creates ASRs for scrollframes of the anchor of anchored content. r?#layout-reviewers,botond,hiro

This is the most complicated and intricate patch in this series.

We want to assign the ASR of the anchor to the anchored content. But there is no painting relationship between them. Meaning that BuildDisplayList for the anchor might be called before or after BuildDisplayList for the anchored content.

If BuildDisplayList is called for the anchor before the anchored content we want to make sure that any scroll frames containing the anchor are activated. This is easy on desktop as all scroll frames that want it are activated. But on android we don't do that yet. That's where bug 1995759 comes in to activate all scroll frames when anchor pos is used.

If BuildDisplayList is called for the anchor after the anchored content then we want to activate any scroll frames containing the anchor during the BuildDisplayList call for the anchored content. That's one of the main things that this patch does. We create a new function DecideScrollableLayerEnsureDisplayport that always set a minimal display port to do that for us (it's a simplified version of DecideScrollableLayer).

Then we use our knowledge that the anchor is in the containing block of the anchored content to walk the scroll frame ancestors of the anchor until we reach the anchored content's containing block. Once we've collected all the scroll frames we can create the ASR structs.

Comment 6

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1988030. Detect and reject an anchor that is outside of the positioned frame's containing block. r?#layout-reviewers

This should be the case but due to spec issues that we are still getting sorted out in bug 1997026 it does not currently hold with our existing code that accurately implemented an older version of the spec. The anchor pos async scroll code in this bug depends on this condition even if other anchor pos code seems to be okay without it as of now.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/537725a5c4aa
https://hg.mozilla.org/integration/autoland/rev/8ac63a73e64d
Adjust nsLayoutUtils::GetAsyncScrollableAncestorFrame to be CSS anchor pos aware. r=layout-reviewers,layout-anchor-positioning-reviewers,hiro,emilio
https://github.com/mozilla-firefox/firefox/commit/e7619a7efccc
https://hg.mozilla.org/integration/autoland/rev/d2942a47bde5
Adjust DisplayPortUtils::OneStepInAsyncScrollableAncestorChain to be CSS anchor pos aware. r=hiro,layout-reviewers,layout-anchor-positioning-reviewers,emilio
https://github.com/mozilla-firefox/firefox/commit/e53645f574d4
https://hg.mozilla.org/integration/autoland/rev/83e77e1ff562
Create nsLayoutUtils::GetASRAncestorFrame and OneStepInASRChain that walks only scroll frames that are currently async scrollable in the ASR order. r=botond,hiro,layout-reviewers,layout-anchor-positioning-reviewers,emilio
https://github.com/mozilla-firefox/firefox/commit/7cd59a61c6a0
https://hg.mozilla.org/integration/autoland/rev/420f945b4828
Allow passing a limit ancestor to DisplayPortUtils::OneStepInASRChain that we don't walk past. r=hiro,layout-reviewers
https://github.com/mozilla-firefox/firefox/commit/1816a3d49caa
https://hg.mozilla.org/integration/autoland/rev/b5dfa95f5b43
Create a function that activates and creates ASRs for scrollframes of the anchor of anchored content. r=hiro,layout-reviewers,layout-anchor-positioning-reviewers,botond,emilio
https://github.com/mozilla-firefox/firefox/commit/237e8563f656
https://hg.mozilla.org/integration/autoland/rev/7359f809caf5
Detect and reject an anchor that is outside of the positioned frame's containing block. r=layout-reviewers,emilio

Comment 8

[amarc]

Backed out for causing build bustages

• Backout link
• Push with failures
• Failure Log

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/0793c4b404d9
https://hg.mozilla.org/integration/autoland/rev/7df984ea1a2d
Adjust nsLayoutUtils::GetAsyncScrollableAncestorFrame to be CSS anchor pos aware. r=layout-reviewers,layout-anchor-positioning-reviewers,hiro,emilio
https://github.com/mozilla-firefox/firefox/commit/3a7c8be81f6e
https://hg.mozilla.org/integration/autoland/rev/b589662e09f5
Adjust DisplayPortUtils::OneStepInAsyncScrollableAncestorChain to be CSS anchor pos aware. r=hiro,layout-reviewers,layout-anchor-positioning-reviewers,emilio
https://github.com/mozilla-firefox/firefox/commit/5b42ac4317bf
https://hg.mozilla.org/integration/autoland/rev/cba51c6f762b
Create nsLayoutUtils::GetASRAncestorFrame and OneStepInASRChain that walks only scroll frames that are currently async scrollable in the ASR order. r=botond,hiro,layout-reviewers,layout-anchor-positioning-reviewers,emilio
https://github.com/mozilla-firefox/firefox/commit/1d3aea828626
https://hg.mozilla.org/integration/autoland/rev/6d1306b4671c
Allow passing a limit ancestor to DisplayPortUtils::OneStepInASRChain that we don't walk past. r=hiro,layout-reviewers
https://github.com/mozilla-firefox/firefox/commit/827aa14e00b3
https://hg.mozilla.org/integration/autoland/rev/9769ef682f6b
Create a function that activates and creates ASRs for scrollframes of the anchor of anchored content. r=hiro,layout-reviewers,layout-anchor-positioning-reviewers,botond,emilio
https://github.com/mozilla-firefox/firefox/commit/970db2137c09
https://hg.mozilla.org/integration/autoland/rev/fa7ec7d8ecb5
Detect and reject an anchor that is outside of the positioned frame's containing block. r=layout-reviewers,emilio
https://github.com/mozilla-firefox/firefox/commit/5d654d58219b
https://hg.mozilla.org/integration/autoland/rev/7049e5052189
1988032: apply code formatting via Lando

Comment 10

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/7df984ea1a2d
https://hg.mozilla.org/mozilla-central/rev/b589662e09f5
https://hg.mozilla.org/mozilla-central/rev/cba51c6f762b
https://hg.mozilla.org/mozilla-central/rev/6d1306b4671c
https://hg.mozilla.org/mozilla-central/rev/9769ef682f6b
https://hg.mozilla.org/mozilla-central/rev/fa7ec7d8ecb5
https://hg.mozilla.org/mozilla-central/rev/7049e5052189