LibWeb: Remove per-element computed style overrides

[kalenikaliaksandr]

Element-specific computed style adjustments existed in the Rust style computation core and a virtual method on Element. The latter was still required for element-backed shadow pseudo-elements and animation style updates, so the two implementations could silently diverge over time.

Expose a combined box transformation and element adjustment through the Rust FFI and use it for the remaining side paths and per-frame animation samples. Remove the Element virtual and its 20 HTML and SVG overrides. Adjusted animation samples preserve input and select line heights, SVG positioning, and table alignment throughout animated style updates.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: cb204ac6-5b20-4c4e-a2d9-ac3c1b34b3fa

📥 Commits

Reviewing files that changed from the base of the PR and between 28908d5 and c1248dd.

📒 Files selected for processing (46)

• Libraries/LibWeb/CSS/StyleComputer.cpp
• Libraries/LibWeb/CSS/StyleComputer.h
• Libraries/LibWeb/DOM/Element.h
• Libraries/LibWeb/HTML/HTMLAudioElement.cpp
• Libraries/LibWeb/HTML/HTMLAudioElement.h
• Libraries/LibWeb/HTML/HTMLBRElement.cpp
• Libraries/LibWeb/HTML/HTMLBRElement.h
• Libraries/LibWeb/HTML/HTMLButtonElement.cpp
• Libraries/LibWeb/HTML/HTMLButtonElement.h
• Libraries/LibWeb/HTML/HTMLCanvasElement.cpp
• Libraries/LibWeb/HTML/HTMLCanvasElement.h
• Libraries/LibWeb/HTML/HTMLElement.cpp
• Libraries/LibWeb/HTML/HTMLElement.h
• Libraries/LibWeb/HTML/HTMLEmbedElement.cpp
• Libraries/LibWeb/HTML/HTMLEmbedElement.h
• Libraries/LibWeb/HTML/HTMLFrameElement.cpp
• Libraries/LibWeb/HTML/HTMLFrameElement.h
• Libraries/LibWeb/HTML/HTMLFrameSetElement.cpp
• Libraries/LibWeb/HTML/HTMLFrameSetElement.h
• Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
• Libraries/LibWeb/HTML/HTMLIFrameElement.h
• Libraries/LibWeb/HTML/HTMLImageElement.cpp
• Libraries/LibWeb/HTML/HTMLImageElement.h
• Libraries/LibWeb/HTML/HTMLInputElement.cpp
• Libraries/LibWeb/HTML/HTMLInputElement.h
• Libraries/LibWeb/HTML/HTMLMediaElement.cpp
• Libraries/LibWeb/HTML/HTMLMediaElement.h
• Libraries/LibWeb/HTML/HTMLMeterElement.cpp
• Libraries/LibWeb/HTML/HTMLMeterElement.h
• Libraries/LibWeb/HTML/HTMLObjectElement.cpp
• Libraries/LibWeb/HTML/HTMLObjectElement.h
• Libraries/LibWeb/HTML/HTMLProgressElement.cpp
• Libraries/LibWeb/HTML/HTMLProgressElement.h
• Libraries/LibWeb/HTML/HTMLSelectElement.cpp
• Libraries/LibWeb/HTML/HTMLSelectElement.h
• Libraries/LibWeb/HTML/HTMLTableElement.cpp
• Libraries/LibWeb/HTML/HTMLTableElement.h
• Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp
• Libraries/LibWeb/HTML/HTMLTextAreaElement.h
• Libraries/LibWeb/Rust/src/css/style_compute.rs
• Libraries/LibWeb/SVG/SVGElement.cpp
• Libraries/LibWeb/SVG/SVGElement.h
• Libraries/LibWeb/SVG/SVGSymbolElement.cpp
• Libraries/LibWeb/SVG/SVGSymbolElement.h
• Tests/LibWeb/Text/expected/css/animated-post-compute-adjustments.txt
• Tests/LibWeb/Text/input/css/animated-post-compute-adjustments.html

💤 Files with no reviewable changes (41)

• Libraries/LibWeb/HTML/HTMLFrameElement.h
• Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
• Libraries/LibWeb/HTML/HTMLFrameElement.cpp
• Libraries/LibWeb/HTML/HTMLEmbedElement.h
• Libraries/LibWeb/HTML/HTMLObjectElement.h
• Libraries/LibWeb/HTML/HTMLCanvasElement.h
• Libraries/LibWeb/HTML/HTMLBRElement.cpp
• Libraries/LibWeb/HTML/HTMLButtonElement.cpp
• Libraries/LibWeb/HTML/HTMLImageElement.cpp
• Libraries/LibWeb/HTML/HTMLMeterElement.h
• Libraries/LibWeb/HTML/HTMLAudioElement.h
• Libraries/LibWeb/HTML/HTMLElement.h
• Libraries/LibWeb/SVG/SVGElement.h
• Libraries/LibWeb/HTML/HTMLIFrameElement.h
• Libraries/LibWeb/HTML/HTMLProgressElement.cpp
• Libraries/LibWeb/HTML/HTMLProgressElement.h
• Libraries/LibWeb/HTML/HTMLMeterElement.cpp
• Libraries/LibWeb/DOM/Element.h
• Libraries/LibWeb/HTML/HTMLSelectElement.h
• Libraries/LibWeb/HTML/HTMLImageElement.h
• Libraries/LibWeb/HTML/HTMLMediaElement.h
• Libraries/LibWeb/HTML/HTMLBRElement.h
• Libraries/LibWeb/HTML/HTMLFrameSetElement.cpp
• Libraries/LibWeb/HTML/HTMLFrameSetElement.h
• Libraries/LibWeb/HTML/HTMLButtonElement.h
• Libraries/LibWeb/HTML/HTMLElement.cpp
• Libraries/LibWeb/HTML/HTMLCanvasElement.cpp
• Libraries/LibWeb/HTML/HTMLObjectElement.cpp
• Libraries/LibWeb/HTML/HTMLTextAreaElement.h
• Libraries/LibWeb/SVG/SVGSymbolElement.h
• Libraries/LibWeb/HTML/HTMLInputElement.cpp
• Libraries/LibWeb/HTML/HTMLSelectElement.cpp
• Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp
• Libraries/LibWeb/HTML/HTMLTableElement.cpp
• Libraries/LibWeb/HTML/HTMLAudioElement.cpp
• Libraries/LibWeb/HTML/HTMLInputElement.h
• Libraries/LibWeb/HTML/HTMLMediaElement.cpp
• Libraries/LibWeb/HTML/HTMLEmbedElement.cpp
• Libraries/LibWeb/SVG/SVGSymbolElement.cpp
• Libraries/LibWeb/HTML/HTMLTableElement.h
• Libraries/LibWeb/SVG/SVGElement.cpp

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📝 Walkthrough

Walkthrough

The change moves element-specific computed-style adjustments into Rust and shared StyleComputer helpers. Adjustments now run during normal, pseudo-element, and post-animation style computation. Element-level adjustment overrides and related tests were updated.

Changes

Element style adjustment pipeline

Layer / File(s)	Summary
Rust adjustment computation Libraries/LibWeb/Rust/src/css/style_compute.rs	Rust now returns combined box-type and element-style adjustments. Element-specific rules use the transformed display and text alignment.
StyleComputer integration and validation Libraries/LibWeb/CSS/StyleComputer.*, Tests/LibWeb/Text/input/css/animated-post-compute-adjustments.html, Tests/LibWeb/Text/expected/css/animated-post-compute-adjustments.txt	StyleComputer applies adjustments during normal, pseudo-element, and animated computation. Tests cover line height, position, text alignment, and display.
Element-specific hook removal Libraries/LibWeb/DOM/Element.h, Libraries/LibWeb/HTML/*, Libraries/LibWeb/SVG/*	The adjust_computed_style interface and HTML/SVG overrides were removed. Their adjustment rules are handled by the shared pipeline.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant StyleComputer
  participant ComputedProperties
  participant rust_adjust_element_style
  StyleComputer->>ComputedProperties: collect animation results
  StyleComputer->>rust_adjust_element_style: compute animated element adjustments
  rust_adjust_element_style-->>StyleComputer: return combined adjustments
  StyleComputer->>ComputedProperties: apply adjusted style properties

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Possibly related PRs

• LadybirdBrowser/ladybird#10712: Both changes modify StyleComputer and animation-aware style computation.
• LadybirdBrowser/ladybird#10772: Both changes replace the previous box-type and C++ element-adjustment flow with Rust style computation.
• LadybirdBrowser/ladybird#10811: Both changes modify StyleComputer and Rust style adjustment handling.

Suggested reviewers: awesomekling

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly matches the changes by removing Element overrides and using combined Rust FFI adjustments for animated styles.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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