layout: Share styles to inline box children via SharedInlineStyles (#36896)

`TextRun`s use their parent style to render. Previously, these styles
were cloned and stored directly in the box tree `TextRun` and resulting
`TextFragment`s. This presents a problem for incremental layout.
Wrapping the style in another layer of shared ownership and mutability
will allow updating all `TextFragment`s during repaint-only incremental
layout by simply updating the box tree styles of the original text
parents.

This adds a new set of borrows when accessing text styles, but also
makes it so that during box tree block construction
`InlineFormattingContext`s are created lazily and now
`InlineFormattingContextBuilder::finish` consumes the builder, making
the API make a bit more sense. This should also improve performance of
box tree block construction slightly.

Testing: This should not change observable behavior and thus is covered
by existing WPT tests.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
This commit is contained in:
Martin Robinson 2025-05-12 11:38:50 +02:00 committed by GitHub
parent db83601b62
commit a0dd2c1beb
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24 changed files with 369 additions and 187 deletions

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@ -142,7 +142,7 @@ impl<'a, 'dom> ModernContainerBuilder<'a, 'dom> {
.filter_map(|job| match job {
ModernContainerJob::TextRuns(runs) => {
let mut inline_formatting_context_builder =
InlineFormattingContextBuilder::new();
InlineFormattingContextBuilder::new(self.info);
for flex_text_run in runs.into_iter() {
inline_formatting_context_builder
.push_text(flex_text_run.text, &flex_text_run.info);